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zut

[!NOTE] Fork notice: zut is an independent fork of zot adapted for my own workflow but feel free to use it too.

What is it?

Yet another coding agent harness, lightweight and written (vibe-slopped) in go.

one static binary.
built-in providers for Anthropic, OpenAI/Codex/Responses, Kimi, DeepSeek, Google Gemini/Vertex, GitHub Copilot, Bedrock, Azure OpenAI, OpenRouter, Groq, Cerebras, xAI, Together, Hugging Face, Mistral, Moonshot, Z.AI, Xiaomi, MiniMax, Fireworks, Vercel AI Gateway, OpenCode, Cloudflare AI, and Ollama/local models.
seven core built-in tools (read, write, edit, bash, create_worktree, lsp, and web_search); the conditional skill tool is available when skills are enabled. See docs/web-search.md for web-search egress and availability boundaries.
three run modes (interactive tui, print, json).
built-in telegram bot.
extensions in any language via subprocess + json-rpc. None installed by default; opt in with zut ext install or zut --ext. See docs/extensions.md.
user and extension themes via JSON; see docs/themes.md.
standing instructions via AGENTS.md files (global and per-project); see Persistent instructions.
reusable instructions via SKILL.md files; see docs/skills.md.
named subagent profiles from ~/.agents/agents/*.md; see docs/subagents.md.
portable agents from local directories, .zut files, or temporary public GitHub downloads; see docs/zutfiles.md.

Install

One-liner (macOS, Linux)

curl -fsSL https://raw.githubusercontent.com/bnema/zut/main/install.sh | bash

Detects your OS and architecture, downloads the latest release from GitHub, verifies the SHA-256 against the release's checksums.txt, extracts the binary, and drops it in /usr/local/bin, ~/.local/bin, or ~/bin, whichever is writable first. Pass a version or prefix to pin:

curl -fsSL https://raw.githubusercontent.com/bnema/zut/main/install.sh | bash -s -- v0.1.0 ~/bin

One-liner (Windows, PowerShell)

iwr -useb https://raw.githubusercontent.com/bnema/zut/main/install.ps1 | iex

Drops zut.exe into $HOME\bin and adds it to the user PATH if missing. Open a fresh terminal afterwards.

go install

go install github.com/bnema/zut/cmd/zut@latest

The installed binary reports the tagged module version and supports zut update.

From source

git clone https://github.com/bnema/zut
cd zut
make help         # list the important developer commands
make build        # produces ./bin/zut (0.0.0-dev by default)
make install      # install the current checkout with go install
make go-install   # install the latest published module version

make go-install GO_INSTALL_VERSION=v0.1.0 installs a specific published version. make install is different: it installs the current checkout as a development build.

Prebuilt binaries

Every release on the releases page ships archives for Linux, macOS, and Windows on amd64 and arm64 (except windows/arm64), plus a checksums.txt file. Download, verify, chmod +x, and drop on your $PATH.

Authenticate

The easiest way is to just run zut and type /login. The TUI opens even without credentials and walks you through a browser-based login flow.

Credential lookup order

--api-key flag
provider-specific env var (ANTHROPIC_API_KEY, OPENAI_API_KEY, KIMI_API_KEY, MOONSHOT_API_KEY, DEEPSEEK_API_KEY, GEMINI_API_KEY, GOOGLE_API_KEY, GROQ_API_KEY, OPENROUTER_API_KEY, MISTRAL_API_KEY, XAI_API_KEY, CEREBRAS_API_KEY, TOGETHER_API_KEY, HF_TOKEN, ZAI_API_KEY, XIAOMI_API_KEY, MINIMAX_API_KEY, FIREWORKS_API_KEY, AI_GATEWAY_API_KEY, COPILOT_GITHUB_TOKEN, GITHUB_COPILOT_TOKEN, and others for provider-specific backends)
$ZUT_HOME/auth.json (API key or OAuth token; mode 0600)

$ZUT_HOME defaults to:

All platforms: $XDG_STATE_HOME/zut when XDG_STATE_HOME is set
macOS fallback: ~/Library/Application Support/zut
Linux fallback: ~/.local/state/zut
Windows fallback: %LOCALAPPDATA%\zut

API keys from commands

To keep an API key in a password manager instead of auth.json, configure an api_key_command for the provider:

{
  "anthropic": {
    "api_key_command": {
      "program": "op",
      "args": ["read", "op://Work/Anthropic/credential"],
      "timeout_ms": 120000
    }
  }
}

For a provider added through models.json, put the same credential object under additional_api_key_creds using its provider ID. program is executed directly, without a shell, so each argument must be a separate args entry. timeout_ms is optional and defaults to 120 seconds.

zut runs the command only when that provider is selected, not while checking login status or refreshing model catalogs in the background. Successful output is cached in memory for the rest of the zut process and is never written to disk. The command must print one non-empty line to stdout; zut removes trailing CR/LF characters, limits output to 64 KiB, and does not include command output in errors. Saving a normal key through /login replaces the command configuration, and /logout removes it.

Treat auth.json as executable configuration: anyone who can modify it can cause zut to run a program under your user account. zut does not interpret ! prefixes or execute command strings through a shell.

`/login` flow

Run zut and type /login. Pick one of two methods:

API key: a small local web server starts on 127.0.0.1:<free-port>, your browser opens a form, you pick a provider from the full API-key provider list, paste the key, and zut saves it to auth.json if accepted. Providers with a lightweight model-list endpoint are probed before saving; provider backends that need extra project/account env vars are saved directly.
Subscription: use your Claude Pro/Max, ChatGPT Plus/Pro, Kimi Code, SuperGrok/X Premium, or GitHub Copilot subscription. DeepSeek and Google Gemini do not have a subscription login path. For those, use the API-key flow.
- Anthropic and OpenAI pin the browser callback to fixed provider-specific ports (localhost:53692 for Anthropic, localhost:1455 for OpenAI) because those are the only ports their auth servers will redirect to.
- Anthropic uses the Claude Code OAuth flow. Messages go to api.anthropic.com with a bearer token and the Claude Code identity headers.
- OpenAI uses the Codex CLI OAuth flow. Messages go to chatgpt.com/backend-api/codex/responses with the chatgpt-account-id extracted from the returned id_token.
- Kimi uses the Kimi Code device-code OAuth flow. zut opens the verification URL, polls until you approve it in the browser, then sends messages to api.kimi.com/coding/v1 with the Kimi Code identity headers.
- xAI uses a device-code OAuth flow. zut opens a prefilled authorization URL, polls for approval, and uses the resulting token with the xAI API.
- GitHub Copilot uses GitHub's device-code login flow. zut stores the GitHub access token and exchanges it for short-lived Copilot inference tokens on demand.

Note on subscription login. The OAuth client IDs used are the ones published in Anthropic's Claude Code CLI, OpenAI's Codex CLI, Kimi Code CLI, xAI's device flow, and GitHub Copilot's device-code flow. Reusing them from a third-party tool may be against their terms of service and may be revoked at any time. Use it at your own risk; the API-key flow is the safe default.

Token refresh

OAuth access tokens are short-lived (Anthropic ~8h, OpenAI ~30d; Kimi, xAI, and GitHub Copilot also use refresh/exchange flows). zut refreshes or exchanges them automatically:

At every credential lookup, zut checks the stored expiry and, if past it (with a 60s safety margin), hits the provider's oauth/token endpoint with the stored refresh_token, persists the new access_token, refresh_token, and expiry back to auth.json, and hands the fresh token to the client.
The telegram bridge additionally refreshes once per turn so a bot that runs for days keeps working without manual intervention.
If the refresh itself fails (the refresh_token was revoked, or the account was logged out everywhere), the error bubbles up to the caller: the TUI shows it in the status line, the bot replies with it in your DM. Run /login to get a fresh token pair.

All data lives under $ZUT_HOME:

$ZUT_HOME/
├── config.json         # last-used provider/model/theme and persistent settings
├── auth.json           # api keys and oauth tokens (mode 0600)
├── sessions/           # jsonl transcripts, one dir per cwd
├── models-cache.json   # live /v1/models discovery cache (6h ttl)
├── AGENTS.md           # optional: global instructions appended to the prompt
├── SYSTEM.md           # optional: replaces the built-in identity; addenda remain
├── skills/             # optional: user SKILL.md files
├── themes/             # optional: user theme JSON files
├── extensions/         # installed extensions, one dir per extension
└── logs/               # app log files

Drop a SYSTEM.md in $ZUT_HOME to replace the built-in identity for every run. Existing append addenda, including AGENTS.md, skills, and enabled Ponytail coding mode, remain layered on top. --system-prompt wins per invocation unless a selected replace-mode subagent profile supplies the child's identity. Delete the file to revert to the default identity.

Ponytail coding mode is enabled by default, including when an existing config.json does not contain a ponytail_enabled field. When disabled, its compact guidance is omitted from resolved system prompts; when enabled, the guidance tells the model to apply itself only to engineering work. The setting persists its explicit on/off choice in $ZUT_HOME/config.json and can be changed from /settings. It is advisory guidance only: it does not change tool permissions, confirmations, jail behavior, or sandboxing.

A selected subagent profile with systemPromptMode: replace supplies the child's base identity even when --system-prompt was provided for the parent run. Global append addenda, including enabled Ponytail guidance, still follow their normal inclusion rules.

Persistent instructions (AGENTS.md)

Use AGENTS.md to give zut standing instructions that layer on top of the default system prompt, without replacing it. This is the friendliest way to shape behavior (for example, taming local models that jump straight to code edits) because it adds guidance rather than taking over the base identity the way SYSTEM.md does.

zut discovers AGENTS.md files automatically at startup and loads them in this order:

$ZUT_HOME/AGENTS.md (global, machine-wide instructions that apply to every project).
Every AGENTS.md from the filesystem root down to the current working directory. More specific (deeper) files may override earlier ones. This includes ~/AGENTS.md when the working directory is inside your home directory.

All discovered files are appended to the prompt in that order, so a global baseline can be refined per project. To list the active Zutfile agent, loaded context paths, extensions, and user-installed skills above the interactive transcript, enable show loaded resources at startup in /settings. The agent section appears only for zut run, the setting is off by default, built-in skills are omitted, and the displayed lists are not sent to the model or stored in the session transcript.

For a general, non-project-specific instruction set, put your rules in $ZUT_HOME/AGENTS.md, for example:

Treat questions and discussions as requests for explanation. Do not edit files or run tools unless explicitly asked to make a change. Ask before modifying code.

AGENTS.md vs the other mechanisms:

Mechanism	Scope	Effect
`$ZUT_HOME/AGENTS.md`	global, every run	appended to the default prompt
`./AGENTS.md` (and parent dirs)	project	appended to the default prompt
`$ZUT_HOME/SYSTEM.md`	global, every run	replaces the built-in identity; append addenda remain
`--append-system-prompt <text>`	single run	appends for one invocation (repeatable)
`--system-prompt <text>`	single run	replaces the built-in identity for one invocation; append addenda remain

Note: zut does not read a CLAUDE.md instruction file. The only Claude-compatible thing it picks up is skills under .claude/skills/. If you are migrating from Claude Code, move that content into AGENTS.md (global or per-project) and zut will use it.

Changelog on update

The first time you launch a newer zut binary, the TUI shows the GitHub release notes once in a dismissible overlay. Press any key to close. The version is recorded in config.json's last_changelog_shown so the same release notes never reappear. Fresh installs don't see a changelog (no upgrade has happened yet). Development builds (0.0.0-dev) skip both the update and changelog requests and print dev version detected; skipping update check. For release builds, the fetch is best-effort: a network failure or a missing release page silently skips, with another attempt on the next launch.

Usage

zut                              # interactive tui
zut "fix the failing test"       # tui, pre-filled prompt
zut -p "list all go files"       # print final text, exit
zut -p --stats stats.json "task" # print final text and write generation stats
zut --json "refactor main.go"    # newline-delimited json events, exit
zut --continue                   # resume the most recent session for this cwd
zut --resume                     # pick a session to resume
zut --list-models                # show supported models
zut --help

Print-mode stats contain provider, model, prompt_tokens, reasoning_tokens, generated_output_tokens, and elapsed_ms. Counts cover all model turns triggered by the prompt, including tool loops. Prompt tokens include cache reads and writes. reasoning_tokens is null when the provider does not report a separate count; in that case generated_output_tokens is the provider's total output count and may include reasoning. Elapsed time covers the agent run, not startup and credential resolution. The file is written only after a successful run.

Flags

Flag	Description
`--provider <id>`	Pick the provider (for example `anthropic`, `openai`, `openai-codex`, `kimi`, `google`, `github-copilot`, `groq`, `openrouter`, `amazon-bedrock`, `ollama`; see Providers).
`--model <id>`	Pick the model (see `--list-models`).
`--api-key <key>`	Override the API key.
`--base-url <url>`	Override the provider base URL (tests, self-hosted).
`--insecure`	Skip TLS certificate verification for the explicit `--base-url` endpoint or a `baseUrl` defined for a user model in `models.json` (self-signed local/internal inference servers). Built-in providers, auth, and model discovery keep normal TLS verification.
`--system-prompt <text>`	Replace the default system prompt for this run (also overrides `$ZUT_HOME/SYSTEM.md`).
`--append-system-prompt <text>`	Append text to the system prompt (repeatable).
`--reasoning off\|minimum\|low\|medium\|high\|xhigh\|max`	Set the reasoning level on supported models (default: off). `max` is a separate opt-in tier above `xhigh`.
`--stats <path>`	With `-p`/`--print`, write generation statistics as JSON.
`-c`, `--continue`	Resume the latest session for this cwd.
`-r`, `--resume`	Pick a session to resume.
`--session <path>`	Resume a specific session file.
`--no-session`	Don't read or write session files.
`--cwd <path>`	Use `<path>` as the working directory.
`--no-tools`	Disable all tools.
`--no-lsp`	Disable the built-in LSP/linter tool for this run.
`--tools <csv>`	Only enable the listed tools. Include `lsp` to select it explicitly. An explicit list must include `web_search` to retain or opt into web search for that invocation; explicitly including it overrides the persisted web-search setting for that invocation.
`--max-steps <n>`	Cap agent loop iterations (default 50).
`-e`, `--ext <path>`	Load an extension from `<path>` for this run (repeatable; wins against installed extensions of the same name).
`--no-ext`	Skip extension discovery for this run. `--ext` still works on top, so `--no-ext --ext ./x` runs only `x`.
`--no-skill`	Disable all skills, including built-ins. No `skill` tool is registered and the system prompt has no skill manifest.
`--no-yolo`	Confirm every tool call before it runs (interactive TUI only). A dialog shows the tool name and a one-line preview of its args, while edit calls show the proposed diff in the tool panel, with four choices: yes, yes-always-this-tool-this-session, yes-always-this-session, no. Press `/` while the dialog is focused to run a slash command first; closing its input or child dialog returns to the pending confirmation. Ignored with a stderr warning in print / json / rpc modes, where tools still run freely so scripts and automation keep working.

Tools

read: read text files, or inline images (PNG, JPEG, GIF, WebP).
write: create or overwrite files, making parent directories as needed.
edit: one or more exact-match replacements in an existing file.
bash: run a command in the session cwd with merged stdout/stderr and a timeout. On Unix, zut uses /bin/bash -c when available, then bash -c from PATH, and falls back to POSIX /bin/sh -c when Bash is unavailable. On Windows, it uses cmd /C. macOS ships Bash 3.2 by default, so newer Bash features may be unavailable.
create_worktree: create a new branch from the current HEAD and check it out persistently. A repository with no configured root and no .worktrees directory first returns bootstrap guidance without making changes; the agent asks whether to use the repository default or an external root, then retries with bootstrap_root. The choice is saved privately in local Git config. Choosing .worktrees creates <repository-root>/.worktrees/<branch> and adds /.worktrees/ to the root .gitignore; an absolute external root leaves tracked repository files and the root .gitignore unchanged. The tool never copies uncommitted or ignored files, and it refuses an existing branch or worktree path.
lsp: query configured language servers and linters for diagnostics, definitions, references, hover information, symbols, renames, code actions, capabilities, and raw protocol requests. LSP servers use stdio JSON-RPC; project lsp.json files can add or override servers and CLI linters. Diagnostics are bounded, sorted, deduplicated by path/severity/code/start position, and repeated issues are grouped before they reach the model. See docs/lsp.md.
web_search: search the public web through DuckDuckGo HTML and return bounded source titles, URLs, and snippets. Enabled by default for normal CLI sessions; it is unavailable to bot, default SDK, and packaged-agent runs. See docs/web-search.md.

When the sandbox is on (see /jail), filesystem tools and LSP workspace edits refuse paths outside the session cwd. create_worktree also requires its repository root, configured worktree destination, optional .gitignore, and Git metadata to remain inside the jail. Jail does not sandbox web-search network egress.

Modes

Interactive (default): chat TUI with streaming output, spinner, cost meter, slash commands.
Print: zut -p "prompt" runs the agent to completion and writes only the final assistant text to stdout.
Stream: zut --stream "prompt" runs without the TUI and writes assistant text to stdout as it arrives. Tool activity goes to stderr.
JSON: zut --json "prompt" emits one JSON object per agent event to stdout, newline-delimited. The schema is documented in docs/rpc.md.
RPC: zut rpc runs as a long-lived child process; commands in on stdin, events and responses out on stdout, both as NDJSON. Designed for embedding zut in third-party apps written in any language. See docs/rpc.md for the wire schema and examples/rpc/{python,node,shell,go} for working clients.

When an initial print, stream, or JSON request exceeds the provider context window, zut compacts the existing transcript and continues the already-appended prompt once. Print still writes only the recovered final text, stream keeps assistant text on stdout and tool diagnostics on stderr, and JSON suppresses the recoverable first terminal error so stdout remains JSONL for the successful turn. A compaction failure or a second context-window error remains terminal; this is not a general autonomous-follow-up policy. The same one-shot recovery applies to subagent workers. It does not apply to RPC, SDK, bot, or Telegram requests.

zutfile agents

A zutfile packages an agent's instructions, skills, requirements, and enforced tool permissions as a shareable agent. Run one from a local directory, a packed .zut artifact, a short name, or directly from a public GitHub repository:

zut run ./my-agent
zut run ./my-agent.zut
zut run frkr/zot-archify
zut run acme/agents/code-reviewer --cwd /path/to/project

Single-part names resolve only to a matching local directory or .zut archive. Anyone can publish an agent as a public GitHub repository and run it as owner/repository, or publish a collection and run an agent directory as owner/repository/agent. zut has no built-in owner, official collection, configured registry, or allowlist. For GitHub sources, zut downloads the repository archive into a temporary directory, validates and runs the selected agent, then removes the downloaded source when the command exits. Agent data, consent receipts, and sessions still persist under $ZUT_HOME. See docs/zutfiles.md for authoring, permissions, packaging, and current limitations.

Embedding

Two ways to drive zut from another program:

Go in-process: import github.com/bnema/zut/packages/agent/sdk. One Runtime per project; Prompt(ctx, text, images) returns a channel of Event. Small example in examples/sdk/.
Any language, out-of-process: spawn zut rpc as a subprocess and exchange newline-delimited JSON over its stdin/stdout. Wire format and event schema in docs/rpc.md. Reference clients live under examples/rpc/.

Both interfaces share the same event schema, so transcripts captured by one can be replayed through the other.

Slash commands

Slash command names are case-insensitive in the TUI and messaging backends; arguments keep their original case. Type / in the TUI to open the autocomplete popup. Available commands:

Command	Description
`/help`	Show key bindings and commands.
`/login`	Log in via API key or subscription (opens a dialog).
`/logout [provider]`	Clear credentials for any logged-in provider, or all when omitted. `/logout openai-codex` clears ChatGPT/Codex subscription auth while preserving a public OpenAI API key; `/logout kimi` also disables fallback to the official Kimi Code CLI token until you log in to Kimi through zut again.
`/model`	Pick a model from a list (or `/model <id>` to set directly).
`/reasoning`	Set the reasoning level for subsequent model calls.
`/fast`	Toggle fast mode for subsequent model calls.
`/llama`	Connect to the configured llama.cpp router, load, unload, or remove cached models, and search/download GGUF models from Hugging Face with live progress. Shown after llama.cpp login is configured.
`/sessions`	Resume a previous session for this directory. The picker omits branches created only for tree navigation.
`/fork`	Pick a previous user message and fork the current session after that turn. The selected turn becomes branch context and no provider turn starts during the checkout.
`/session`	Four ops on the current session: `export` to a portable `.zutsession` file, `import` one back in, `fork` from a past user message into a new branch, `tree` to switch between branches. Opens a picker without an argument; direct forms: `/session export [path]`, `/session import <path>`, `/session fork`, `/session tree`. Default export destination is `~/Downloads`. `Esc` `Esc` from an idle, empty editor is a shortcut for `/session tree` when the terminal supplies two parsed bare Escape events.
`/jump`	Scroll the chat to a previous turn (or `/jump <text>` to filter).
`/btw`	Side chat with full context that doesn't add to the main thread.
`/subagents`	Spawn, monitor, and chat with background subagents. Each is a separate long-lived process with bounded lifecycle state, structured results, and optional Git worktree isolation. Named profiles can be selected with `agent`; see docs/subagents.md.
`/skills`	List discovered skills (SKILL.md files) and preview their bodies.
`/compact`	Summarize the transcript into one message to free up context.
`/study`	Run the canned prompt "Read and understand everything in the current directory." so the agent has full project context before you start asking targeted questions. Pass a path — typed, drag-dropped, or selected via `@` — to target a specific file or directory instead: `/study [dir:packages/]`, `/study cmd/zut/main.go`.
`/jail`	Confine tools to the current directory.
`/unjail`	Allow tools to touch paths outside again.
`/reload-ext`	Hot-reload all extensions (re-read manifests, respawn subprocesses, rebuild tool registry).
`/telegram`	Connect, disconnect, or show status of the Telegram bridge (takes `connect` / `disconnect` / `status` as an optional argument; opens a picker without one). When connected, DMs from the paired user become prompts in the running session and the assistant's replies are mirrored back to Telegram. Alias: `/tg`.
`/settings`	Change persistent settings, including web search, inline images, terminal alerts, AI terminal titles, auto-subagents, Ponytail coding mode, fast mode, main/sub-agent LSP access, and the auto-compact threshold. `/fast` is a shortcut for the fast-mode toggle. Saved to `$ZUT_HOME/config.json`; setting changes apply without a restart, while AI title generation waits for the first real prompt.
`/clear`	Clear the chat transcript.
`/exit`	Exit zut.

Extension-registered commands appear under a divider at the bottom of the popup, sorted by name.

Shell escape (`!command`)

Type ! followed by a command to run it directly without going through the model. Everything after the ! is passed to the same shell the bash tool uses (/bin/bash -c when available on Unix, then bash -c from PATH, with POSIX /bin/sh -c as a fallback; cmd /C on Windows), runs in the session working directory, and honors the /jail sandbox. The command, merged output, and exit status are appended to the transcript as user context, so the model can use them on the next turn. Running the command does not itself start a model turn. A running !command shares the busy state with the agent: esc cancels it, and you cannot start one while a turn (or another shell escape) is in flight.

`/sessions`

Shows previous sessions for the current working directory, newest first, with timestamp, model, message count, cost, and the session title. Session entries load in the background and are revealed incrementally in newest-first order; an older result may wait briefly for entries ahead of it so the list never reorders, while the picker keeps showing progress for the remaining entries. Once an entry appears, up/down and enter can select it immediately; esc cancels and closes the picker. zut swaps the current session file for the selected one and replays the full transcript (including tool calls) into the agent. Sessions remember their stored provider and model: resuming rebuilds the live agent when necessary instead of silently using a different model; if that rebuild fails, the current session is left unchanged. Branches created for tree navigation remain available to /session tree but are hidden from this flat picker. A fresh interactive session asks the active model for a concise title after the first real prompt and restores that title when resumed.

`/session`

Four ops on the current session. /session alone opens a picker; each is also runnable directly.

/session export [path]. Writes the running transcript to a portable .zutsession file. Default destination is ~/Downloads/<timestamp>-<session-id>-<prompt-slug>.zutsession. Pass a path to override; a directory is fine (a dated name is built inside), a bare name gets .zutsession appended. The meta's cwd is stripped on the way out so the recipient doesn't see your filesystem layout.

What's included. Only the main chat thread of the running session — messages, tool calls, tool results, compactions, and usage. /subagents subagents are NOT included. Their transcripts, unix-socket inboxes, and per-agent session files are all machine-local; a .zutsession is just a chat transcript and has no way to revive a unix socket on another box. If you want the conversation, copy it out of the dashboard manually.
/session import <path>. Copies a .zutsession file into $ZUT_HOME/sessions/<cwd-hash>/ with a fresh id and the current cwd, then switches the running agent onto it. Imported sessions are first-class: they show up in /sessions and /jump, and in the current-family tree when they are part of that family. Drag-drop paths in the editor are accepted (zut strips the surrounding quotes automatically).
/fork (also available as /session fork). Opens a turn picker (same shape as /jump). Pick any past user message; zut copies the transcript through that turn into a new branch and switches to it without starting a provider request. The parent session stays on disk. Use it to try a different question without polluting the original transcript, or to rewind after the agent went down the wrong path. Use a user-message row in /session tree when you want the prompt restored for editing, including image attachments.
/session tree. Shows the current session's family: its root ancestor and descendants, not unrelated root sessions in the same cwd. Use up/down and enter to choose a row; esc closes the tree. The picker keeps pre-compaction history available as forkable user and assistant messages, while hiding tool calls, tool results, compaction checkpoints, shell/image helper rows, and other internal context. Message rows are indented at their branch points and the current endpoint is tagged [current]. Empty and detached branch points are represented by visible boundary rows. A child whose historical fork point no longer matches after compaction stays discoverable as a detached branch under the parent's current tail rather than disappearing. Parentless sessions are roots; orphaned children (whose parent file was deleted) remain roots.

Selecting a user-message row creates a navigation branch before that message and restores the complete editable draft, including text blocks and image attachments; no provider request is made until you submit it. Selecting an assistant-message row checks out a safe message boundary, and selecting an empty or detached boundary checks out that branch point with an empty editor. Navigation branches are hidden from /sessions but remain in the tree.

/session tree and the double-Escape shortcut use the same checks: a complete current session family must be readable, and no turn, shell escape, compaction, startup/session load, dialog, picker, suggestion, or queued message may be active. The shortcut is two parsed, unmodified bare Esc events within 500 ms from an idle editor with no visible text or pending image. Dialogs, confirmations, panels, pickers, and suggestions keep their existing Escape behavior; busy Escape still cancels, modified Escape is not part of the gesture, and any intervening key or timeout resets it. The shortcut depends on the terminal input path producing those parsed events; /session tree is the explicit equivalent when it is unavailable.

`/jump`

Opens a turn picker for the current session, one row per user prompt, each showing the turn number, how many tools that turn invoked, and the first line of the prompt. up/down to pick, enter to jump, esc to cancel. Any printable rune while the picker is open extends a filter; backspace narrows it back. /jump <text> pre-applies the filter; if exactly one turn matches, zut jumps straight there without showing the picker.

Jumping is non-destructive. The transcript is untouched, the viewport just scrolls so the chosen turn is at the top. A muted line at the top of the chat reads viewing turn N of M, pgdn to catch up. Scroll back to the bottom with pgdn (or keep scrolling with the arrow keys) and the indicator goes away.

`/btw`

Opens a side-chat overlay with the full main session as frozen context, so you can ask quick clarifying questions ("does asyncio.gather() catch exceptions?", "btw the bundle budget is 10MB", "what's the default fetch timeout?") without bloating the main thread.

Each question runs an isolated agent turn against system + main transcript + side-chat history so far. The side chat has the same tools and guards as the main chat, including per-tool confirmation when --no-yolo is active. Responses, tool calls, and tool results stay in the overlay. When you press esc to close, nothing has been added to the main session and subsequent main-thread turns don't re-read any of the side-chat exchanges, keeping the running context window lean.

/btw                              # open the overlay, type questions interactively
/btw does PUT replace the whole resource?

Inside the overlay: enter sends, esc cancels an in-flight call (or closes the overlay if idle), ctrl+c closes immediately. Side-chat exchanges never touch the transcript and aren't persisted to the session file.

`/subagents`

Background subagents that run alongside your main session. Each one is a separate zut subprocess with its own model loop, persistent session file, versioned JSONL control protocol, structured turn result, and lifecycle state. Shared checkout mode preserves the historical behavior; worktree mode creates a temporary detached Git worktree, captures a patch and changed-file list, and never merges automatically.

Choose the workspace deliberately. Use isolation:"worktree" for parallel coding so children cannot edit the host checkout. Use shared mode for read-only review or explicitly coordinated work. Worktree isolation is an accident-prevention guardrail, not a security sandbox.

/subagents                                      # open the dashboard
/subagents new <task>                           # spawn an agent (shared mode)
/subagents new --agent reviewer <task>          # use a named markdown profile
/subagents new --reasoning high <task>          # set child reasoning
/subagents logs <id>                            # open one agent's transcript
/subagents send <id> <text>                     # send a follow-up turn
/subagents result <id>                          # show the structured result reference
/subagents resume-session <id>                  # continue without replaying the task
/subagents restart-task <id>                   # intentionally run the stored task again
/subagents kill <id>                            # cancel gracefully, then force-stop
/subagents remove <id>                          # delete durable state

Dashboard (/subagents with no arg) — a list of every agent for the current session, with process/turn state, queue position, age, workspace mode, and current activity. Keys:

Key	Action
`↑` / `↓`	Move cursor between rows.
`enter`	Open the highlighted agent's transcript view.
`n`	Spawn a new agent (opens an inline task editor; inherits the host's current model).
`p`	One-off prompt editor for the selected row (without entering the transcript).
`R`	Resume a stopped agent in place.
`k`	Kill the selected running agent. Its session and state stay so you can resume it later.
`r`	Remove the selected agent entirely (session + meta gone).
`esc`	Close the dashboard.

Inside an agent's transcript — a chat overlay with an always-on inline composer at the bottom. The conversation flows above it; type and enter to send a follow-up. The view auto-follows streaming output and shows an inline spinner with the agent's current activity (thinking, tool: edit_file, etc.) while it's busy. esc returns to the dashboard.

Switching the spawn model from inside the editor — while composing a task in the n-prompt, type /model on its own line and enter. The standard /model picker pops up; pick a model, the picker closes, and the editor reopens with your typed task intact and the new model pinned for the spawn.

Session scoping — each agent is stamped with the host session that spawned it and only shows up in that session's dashboard. Swap sessions with /sessions and the dashboard re-narrows accordingly. Agents from other sessions keep running in the background and reappear when you switch back.

Persistence across zut restarts — every spawn writes a durable manifest, lifecycle summary, append-only event log, session file, and structured result.json under $ZUT_HOME/subagents/agents/<id>/. On the next zut launch the compact summary restores each agent as detached without replaying its full history. Open its transcript to hydrate the durable event log, then use R or /subagents resume-session <id> to continue the existing session. /subagents restart-task <id> is the explicit operation that intentionally replays the stored task.

Where state lives — per-agent manifests, session files, events, results, and patches live under $ZUT_HOME/subagents/agents/<id>/; inbox sockets are runtime-only and permission-restricted. Shared-mode edits land directly in the repo. Worktree-mode edits are captured as durable patches and changed-file summaries before cleanup.

/session export does NOT bundle subagents. A .zutsession is just the main chat transcript; per-agent state (session file, unix-socket inbox) is machine-local and doesn't round-trip through a JSONL file. To share what an agent said, copy it out of the transcript view manually.

Auto-subagents. With /settings -> auto-subagents on, the main agent gets the canonical subagent_spawn tool and a system-prompt nudge to delegate independent work. The companion subagent_status tool accepts an optional agent_id: omit it to list visible workers, or pass a full id / unique prefix to query one without waiting for completion. It returns privacy-safe JSON metadata with the worker id, lifecycle state (starting, running, completed, failed, cancelled, or detached), underlying process/turn state, timestamps, a bounded first-line task summary, and terminal-result metadata when available; it does not return prompts, transcripts, result output, credentials, provider settings, or filesystem paths. The spawn tool returns the child id and initial state immediately; completion is a durable turn.result with a subagent://<id>/result reference. It accepts named profiles, timeout, max_turns, and isolation:"shared" or isolation:"worktree". Omit max_turns to use the supervisor policy; the default ceiling is 3 and subagents.max_turns changes it. Global concurrency limits apply equally to slash commands, tool calls, and batches. Off by default; toggle from /settings.

Named subagent profiles

zut discovers the common markdown/frontmatter profile layout from ~/.agents/agents/*.md by default. With auto-subagents enabled, the main agent receives [subagents_list] metadata and can select a named profile through subagent_spawn. Profile bodies are applied only to the selected child. See docs/subagents.md for discovery, supported fields, reasoning levels, and examples.

`/settings`

Opens a dialog with every persistent setting. up/down to navigate, enter or space to change the selected row, esc to close (rows that open a sub-view, like model shortcuts, use esc to go back one level first). Changes are written to $ZUT_HOME/config.json without a restart; individual settings document whether they affect the current turn, the next model call, or a later session event. Current settings:

web search — allow the normal CLI agent to send search queries to DuckDuckGo HTML and return bounded public-web sources. Enabled by default; disabling it removes web_search from the current interactive session and future normal CLI runs when no invocation-level tool override applies. If the current command explicitly included --tools web_search (alone or in its CSV list), that higher-precedence opt-in keeps web search enabled for this session and the settings row is read-only with an explanation; run zut without that explicit override to change the persisted default. The setting persists as web_search_enabled. Bot, default SDK, and packaged-agent runs remain unavailable regardless of this setting. See docs/web-search.md.
render images when supported — draw screenshots / read-returned images inline using the terminal's image protocol, or fall back to a text placeholder. Auto-detected from TERM_PROGRAM; the toggle overrides the detection. The row is greyed out and forced off on terminals that don't speak any image protocol.
terminal alerts — emit a terminal bell when the main session stops with work that may need attention, or when an extension raises a structured alert. Enabled by default; changes apply immediately and persist as terminal_alerts_enabled. Terminal emulators may render the bell audibly, visually, or not at all.
AI terminal titles — after the first real prompt of a fresh interactive session, make one small hidden request to the active model and set the terminal title to zut: <title>. The title is limited to 40 Unicode characters, persisted with the session, restored on resume, and never added to the conversation. Enabled by default; disable it to avoid the extra model request. The toggle applies immediately, but title generation still waits for the first real prompt and never starts from startup context, resumed history, or slash commands. Persists as terminal_title_enabled.
auto-subagents — let the main agent spawn background sub-agents in parallel via subagent_spawn and query live state via subagent_status. Off by default. The tools accept named profiles, reasoning, timeout, turn limits, and shared/worktree isolation where applicable; lifecycle and result references are persisted. Completion updates still arrive through the auto-subagents watcher. See /subagents and docs/subagents.md for details.
Ponytail coding mode — include compact engineering guidance in each resolved system prompt; the guidance tells the model to apply it to coding, debugging, and review work rather than ordinary conversation. It favors understanding the real flow, small validated changes, reuse, and preserving safety checks. Enabled by default; changes apply to the next model call and persist as ponytail_enabled in $ZUT_HOME/config.json. It is included by interactive, print, stream, JSON, RPC, subagent, bot, SDK, and Zutfile agents.
fast mode — request the provider's fast tier where supported. It currently uses OpenAI's Fast service tier for OpenAI, OpenAI Responses, and OpenAI Codex models. Off by default; toggle it with /fast or /settings; changes apply on the next model call and persist as fast_mode. Other providers currently return an unsupported-provider error. Fast mode may cost more and depends on the selected model/account.
lsp in main session — enable the built-in lsp tool and code diagnostics for the main agent. Enabled by default; changes persist as lsp_enabled.
lsp in sub-agents — allow newly spawned background sub-agents to use the built-in lsp tool. Enabled by default; changes persist as subagent_lsp_enabled and apply when a child starts.
auto-compact threshold — choose off, 70%, 80%, 85% (default), or 90% of the model's advertised context window. The selected percentage controls automatic compaction before and after interactive turns and persists as auto_compact_threshold. Structural unfinished tails and truncated output continue as before. After a successful after-turn threshold compaction, zut may make at most two hidden, bounded recovery continuations when the assistant's visible text appears to promise future work; clear completed text settles normally, and a newer queued user request wins. An interrupted interactive session retains an outstanding handoff when resumed, including after portable export and import. Manual /compact does not silently start work. off disables percentage-based triggers but keeps manual /compact and automatic recovery from context-window and payload-too-large responses. Truncated-output continuation remains a separate priority rule.
jail new sessions by default: start every new agent with tools confined to its working directory. Off by default. The setting applies to interactive, print, JSON, RPC, and background-agent runs, persists as jail_by_default, and immediately updates the current interactive session. /jail and /unjail remain session-scoped overrides and do not change this default.
compact transcript rendering: reduce visual chrome in the chat transcript. Tool calls render as a quiet header plus indented output instead of a bordered box, and sent messages render without padded background bubbles. Off by default. Changes apply immediately and persist to config.json as compact_mode.
show loaded resources at startup: list the active Zutfile agent (for zut run), loaded AGENTS.md paths, extensions, and user-installed skills in compact sections above the transcript. Built-in skills are omitted. Off by default. Changes apply immediately and persist to config.json as show_instructions_at_startup.
TUI settings: opens a sub-view for input layout in display order: status, working spinner, input, then running subagents. Input style can be plain (default prompt line), lines (separator lines above and below the input), or block (a user-bubble-style input block). Status position places model, usage, and working-directory information above or below the input. Working spinner position places the busy spinner above or below the input. Running subagent position places live delegated-turn rows above or below the input; it defaults below the input and shows the profile or agent ID, current activity, and elapsed time since the last activity/heartbeat. On a short terminal, omitted rows collapse into one count summary so the editor remains visible. Idle, detached, and terminal turns disappear from this area immediately. Changes apply immediately and persist to config.json as tui_input_style, tui_status_position, tui_working_position, and tui_subagent_position (above_input or below_input for the position fields).
reasoning level: choose reasoning for supported models: off, minimum, low, medium, high, xhigh, or max. The max tier is opt-in and sent natively to GPT-5.6 and adaptive-thinking Claude models; unsupported backends clamp it to their highest accepted effort. The change is persisted to config.json and applied to the next model call. Use /reasoning to open this selector directly. The selector only shows distinct levels supported by the active model; models without reasoning support only offer off.
color theme — choose the built-in auto, inherited (from terminal), dark, or light theme, or any JSON theme discovered under $ZUT_HOME/themes or a loaded extension. Built-in and JSON themes follow terminal color capability: truecolor terminals receive RGB output, while RGB values fall back to xterm-256 elsewhere. Theme files can use xterm-256, ANSI, or RGB values for semantic UI colors and can also override syntax colors and spinner frames/messages. Changes apply immediately; if a selected theme file is deleted, zut resets to auto. See docs/themes.md.
model shortcuts — opens a sub-view with nine slots (model 1 ... model 9). enter on a slot opens the same /model selector and binds the chosen provider/model to that slot; backspace clears a slot. Once assigned, press Ctrl+1 ... Ctrl+9 from the editor to switch the active model instantly (the same cross-provider swap /model performs, transcript and cost carried over). Assigning a shortcut does not change the current model. Shortcuts are skipped while a turn is running.

`/skills`

Opens a picker listing every discovered SKILL.md file, built-ins hidden. Each row shows the skill name, source, and description. enter opens the body inline (scrollable with up/down/pgup/pgdn); esc goes back. Re-runs discovery each time it opens, so edits to a SKILL.md during a session are reflected immediately.

`/compact`

Sends the current transcript through the model with a structured summarization prompt. The returned summary replaces the transcript as one synthetic user message, with the last few exchanges kept verbatim for continuity. The status bar's context meter resets. Manual /compact only summarizes; it does not silently start work afterward. Use it when the context meter creeps past ~80%.

zut also auto-compacts in the background after an interactive turn reaches the configured context threshold. Structural unfinished tails and output stopped at the model's token limit continue as before. After a successful after-turn threshold compaction, a visible assistant status that appears to promise future work may receive at most two hidden, bounded recovery continuations; clear completed text settles normally, and a newer queued user request supersedes that recovery. An interrupted interactive session resumes an outstanding hidden handoff without displaying it as a chat message. A new branch keeps that handoff only when it copies the complete effective transcript; /fork or /session tree selection at an earlier turn, and every branch from pre-compaction history, drops it and starts no hidden continuation. Manual /compact does not silently start work, and truncated-output continuation remains a separate priority rule. Choose off, 70%, 80%, 85% (default), or 90% under /settings → auto-compact threshold. You'll see condensing history, esc to cancel above the status bar and an (auto) tag next to the context percentage; esc aborts it without touching the transcript. Turning the percentage trigger off does not disable automatic compaction and retry after a context-window or payload-too-large response.

`/jail`

Enforces a sandbox rooted at the cwd shown in the status bar. read, write, and edit resolve their target path (including through symlinks) and refuse anything outside the sandbox. create_worktree also requires its repository root, Git metadata, optional .gitignore, and configured worktree destination to be inside the sandbox. bash refuses obvious escape patterns (sudo, rm -rf /, leading cd /, cd .., cd ~, chmod -R, dd of=/, and similar) and rejects shell arguments or redirections that point outside the sandbox. The status bar shows jailed, ~/your/cwd while active. Enable jail new sessions by default in /settings to persist this behavior across launches; /unjail then unlocks only the current session.

This is a guardrail against accidents, not a hard security boundary. If you need real isolation, run zut under docker or a proper sandbox.

Sessions

Every interactive or print/json run (unless --no-session) writes a JSONL transcript under $ZUT_HOME/sessions/<cwd-hash>/. Resume any of them with --continue, --resume, --session <path>, or interactively via /sessions inside the TUI. Session metadata stores the provider and model used by that session; resume honors that pair, rebuilding the active agent when it differs and refusing the switch without discarding the current session if rebuilding fails. Empty sessions (the user exited without prompting) are deleted on close so the list stays tidy.

Providers

zut's built-in provider catalog includes:

Subscription-capable: Anthropic Claude Pro/Max (anthropic), OpenAI Codex / ChatGPT Plus/Pro (openai-codex), Kimi Code (kimi), SuperGrok/X Premium (xai), GitHub Copilot (github-copilot).
Direct API providers: Anthropic, OpenAI Chat Completions, OpenAI Responses, DeepSeek, Google Gemini, Kimi/Moonshot, Moonshot CN, Groq, Cerebras, xAI, Together AI, Hugging Face Router, OpenRouter, Mistral, Z.AI, Xiaomi/MiMo token-plan regions, MiniMax global/CN, Fireworks, Vercel AI Gateway, OpenCode/OpenCode Go.
Cloud/platform providers: Amazon Bedrock, Google Vertex AI, Azure OpenAI, Cloudflare Workers AI, Cloudflare AI Gateway.
Local/compatible: Ollama, llama.cpp router mode, and OpenAI-compatible local endpoints via --base-url.

Use /login to store API keys or subscription credentials. /model only shows models from providers that are currently available from env vars, auth.json, Kimi CLI fallback, local Ollama, or a configured llama.cpp router.

Models

--list-models or the /model picker shows the full catalog across all built-in providers. Three sources:

Catalog: models baked into zut, covering Claude, GPT/Codex, Gemini/Gemma, Kimi/Moonshot, DeepSeek, Groq-hosted Llama/Gemma/Compound, OpenRouter-routed models, Bedrock model ids, Vertex model ids, Azure OpenAI deployments, Copilot models, and other provider-specific catalog entries.
Live: IDs discovered from GET /v1/models using your stored API key (cached for 6h in $ZUT_HOME/models-cache.json, refreshed in the background on startup).
Speculative: IDs that appear in the upstream generator but aren't live on the public API yet. They'll 404 today and start working the moment the provider ships them.

The context meter in the status line uses the model's advertised context window to show how much of it your last turn consumed.

Model fallback (rescue)

When a turn fails because of a recoverable provider error — expired token (401), permission denied (403), rate limit (429), provider outage (502/503/504), or a transient network failure — zut opens a rescue picker over the chat instead of just painting a red banner.

The picker is the same vertical list / fuzzy filter UI as /model, but it only shows models from providers you're currently logged in to (env vars, auth.json, Kimi CLI fallback, ollama). The failed model is excluded. Press ↑/↓ to choose, enter to retry the same prompt on the new model, esc to dismiss.

Before the actual provider request fires, the OpenAI / Anthropic / Kimi / DeepSeek / Google / OpenAI-Codex clients also do up to two silent retries with short backoff (250ms, 750ms) on 502/503/504 and connection-reset / EOF-before-headers errors. Most edge-proxy blips disappear without you ever seeing the rescue picker.

A rescue retry always drops launch-time --api-key and --base-url before rebuilding the agent. Those overrides are usually the reason the rescue triggered (bad key, typo'd base URL, corporate gateway only valid for the originally-picked provider), so the retry re-resolves credentials from env vars / auth.json / provider defaults instead. Use /model if you want overrides to stick.

No configuration is required — the candidate list is built dynamically from your active credentials. Bad-request / context-length / serialization errors are NOT routed to the rescue picker, because switching models won't fix them; those still surface as a normal error.

Custom models

Place a models.json in $ZUT_HOME ($XDG_STATE_HOME/zut/ when set, otherwise the platform default above) to add models that aren't in the baked-in catalog or to override existing entries:

{
  "providers": {
    "openai": {
      "models": [
        {
          "id": "gpt-5.5",
          "name": "GPT-5.5",
          "reasoning": true,
          "reasoningLevelMap": {"minimum": "low", "max": ""},
          "contextWindow": 400000,
          "maxTokens": 128000
        }
      ]
    }
  }
}

Supported fields per model: id (required), name, reasoning, reasoningLevelMap, contextWindow, maxTokens, baseUrl, priceInput, priceOutput, priceCacheRead, priceCacheWrite.

reasoningLevelMap is optional. Protocol defaults apply when it is omitted. Add only model-specific exceptions using minimum, low, medium, high, xhigh, or max as keys. Map a key to another level when both inputs are equivalent, or to an empty string or off to remove it. The same effective mapping drives /reasoning and provider requests.

Provider keys are normalized: openai-codex and openai-responses map to openai, anthropic-messages maps to anthropic, moonshot, moonshot-ai, and kimi-code map to kimi, and deepseek-chat and deepseek-ai map to deepseek. Built-in provider ids such as groq, openrouter, github-copilot, amazon-bedrock, google-vertex, azure-openai-responses, fireworks, vercel-ai-gateway, mistral, and xai can also be used directly.

User-defined models show source: user in --list-models and take precedence over both the baked-in catalog and live-discovered models. Adding a models.json does not hide the built-in catalog; entries are merged on top of it. Missing or invalid files are silently ignored.

Custom providers

A top-level provider key that is not a built-in id defines a custom provider. Give it a provider-level baseUrl and an api wire format (openai for OpenAI-compatible Chat Completions, the default, openai-responses for the OpenAI Responses API, or anthropic for the Anthropic Messages API). A model-level baseUrl overrides the provider-level one for that model; an unknown api value falls back to openai with a warning.

{
  "providers": {
    "my-company": {
      "baseUrl": "https://llm.mycompany.com/v1",
      "api": "openai",
      "models": [
        { "id": "company-llm-v2", "name": "Company LLM v2" }
      ]
    }
  }
}

Custom providers are first-class: they appear in --list-models, /model, and /login. models.json never stores secrets. Supply the key through /login, --api-key, or a derived environment variable in upper snake case (so my-company reads MY_COMPANY_API_KEY). Because many self-hosted gateways do not expose a model-list endpoint, custom provider keys are accepted and stored without a verification probe; an invalid key surfaces on the first model call.

To retrieve this custom provider's key from a password manager, add a matching entry to $ZUT_HOME/auth.json:

{
  "additional_api_key_creds": {
    "my-company": {
      "api_key_command": {
        "program": "op",
        "args": ["read", "op://Work/OpenAI/credential"],
        "timeout_ms": 120000
      }
    }
  }
}

The provider IDs in models.json and auth.json must match. Then select the custom model directly:

zut --provider my-company --model company-llm-v2

Kimi Code

zut has built-in Kimi support through the Kimi Coding endpoint and Moonshot's OpenAI-compatible chat API.

zut --provider kimi

By default this uses:

model: kimi-for-coding
base URL: https://api.kimi.com/coding/v1

Credential lookup order for Kimi:

--api-key
KIMI_API_KEY
MOONSHOT_API_KEY
$ZUT_HOME/auth.json
the official Kimi Code CLI token at ~/.kimi/credentials/kimi-code.json, unless disabled by /logout kimi

Use /login for either API-key login or Kimi Code subscription login. The subscription flow uses Kimi Code's device-code OAuth flow: zut opens the verification URL, waits for browser approval, stores the token in auth.json, and refreshes it automatically.

For direct Moonshot API keys or a custom compatible endpoint:

zut --provider kimi --model kimi-k2-0905-preview --base-url https://api.moonshot.ai/v1 --api-key "$KIMI_API_KEY"

Kimi K3 is built in as kimi/k3, moonshotai/kimi-k3, moonshotai-cn/kimi-k3, opencode-go/kimi-k3, openrouter/moonshotai/kimi-k3, and vercel-ai-gateway/moonshotai/kimi-k3. Its output limit is 131,072 tokens on every built-in route.

You can add additional Kimi/Moonshot model IDs to models.json under the kimi provider.

xAI

xAI supports either XAI_API_KEY or /login subscription authentication. The subscription option is labeled Sign in with SuperGrok or X Premium, opens a prefilled device-authorization URL, and refreshes the stored token automatically. The default xAI model is grok-4.5, sent through the Responses API.

DeepSeek

zut has built-in DeepSeek support through DeepSeek's OpenAI-compatible chat API.

zut --provider deepseek

By default this uses:

model: deepseek-v4-pro
base URL: https://api.deepseek.com/v1

Catalog ships with deepseek-v4-pro (reasoning) and deepseek-v4-flash. These are exactly the IDs returned by GET https://api.deepseek.com/models today. You can add additional model IDs to models.json under the deepseek provider.

Credential lookup order for DeepSeek:

--api-key
DEEPSEEK_API_KEY
$ZUT_HOME/auth.json

Use /login and pick api key to paste a DeepSeek key. zut probes /v1/models once and stores the key under deepseek in auth.json.

Auth model: API key only. DeepSeek does not offer a subscription OAuth flow. The /login subscription step lists only Anthropic, OpenAI, and Kimi; DeepSeek shows up only under /login → api key.

Text only at the wire level. DeepSeek's chat-completions endpoint currently rejects the multimodal content schema (unknown variant image_url, expected text). When the active provider is deepseek, zut silently drops ImageBlock parts from outgoing user/tool messages and keeps only the text. Switching back to a vision-capable model (Claude, GPT-4o/5, Gemini) re-sends the image normally because the session file still stores it.

For a custom-compatible endpoint (mirror, gateway, self-host):

zut --provider deepseek --base-url https://my-deepseek-mirror.example.com/v1 --api-key "$DEEPSEEK_API_KEY"

Google Gemini

zut has built-in Google Gemini support through the AI Studio Generative Language API.

zut --provider google

By default this uses:

model: gemini-2.5-pro
base URL: https://generativelanguage.googleapis.com

Catalog ships with gemini-2.5-pro, gemini-2.5-flash, gemini-2.5-flash-lite, gemini-2.0-flash, and gemini-2.0-flash-lite. Live discovery against /v1beta/models adds anything else your key can see.

Credential lookup order for Google:

--api-key
GEMINI_API_KEY
GOOGLE_API_KEY
$ZUT_HOME/auth.json

Use /login and pick api key to paste an AI Studio key. zut probes /v1beta/models once and stores the key under google in auth.json.

Auth model: API key only (this provider). Google does not issue OAuth tokens for consumer Gemini Advanced / Google One AI Premium subscriptions, so there is no "log in with your Google subscription" flow. The /login subscription step quietly downgrades to the api-key form when you pick Google so you don't end up in a dead end. If you need OAuth/service-account auth instead of an API key, use the google-vertex provider below.

Free-tier rate limits. AI Studio's free tier has tight per-minute and per-day caps that vary by model: gemini-2.5-pro is the strictest (a few requests per minute, ~50 per day), Flash and Flash-Lite are far more generous. If a Pro turn 429s with "You exceeded your current quota" while Flash on the same key still works, you've hit the Pro free-tier RPD. Either switch to Flash for agent loops, or enable billing on your AI Studio project to flip the same key from free to pay-as-you-go pricing ($1.25/M input, $10/M output for Pro).

Reasoning levels (--reasoning off|minimum|low|medium|high|xhigh|max, also configurable through /reasoning or in /settings as reasoning level) map differently per generation. max is a distinct opt-in tier above xhigh. GPT-5.6 and adaptive-thinking Claude models receive native max; unsupported providers clamp it to their highest accepted effort. Budget-based providers retain their provider/model caps. Gemini 3.x uses the thinkingLevel enum (MINIMAL/LOW/MEDIUM/HIGH), with Gemini-3-Pro pinned to LOW minimum and HIGH for any medium-or-higher request. off sends no reasoning config. Gemini 2.0 models have no thinking config.

You can add additional Gemini model IDs to models.json under the google provider.

Gemini Enterprise Agent Platform (formerly Google Vertex AI)

zut also has built-in support for Gemini Enterprise Agent Platform, Google's enterprise/GCP-hosted Gemini endpoint. Unlike the AI Studio google provider above, the google-vertex provider supports a Google Cloud API key plus service_account and authorized_user credential files. It does not support consumer Google login or the complete ADC credential chain, such as metadata-server and workload-identity credentials.

zut --provider google-vertex

Required configuration (env vars, read at construction time):

GOOGLE_CLOUD_PROJECT — required, your GCP project id.
GOOGLE_CLOUD_LOCATION — optional, defaults to us-central1.

Credential lookup order for Vertex:

GOOGLE_CLOUD_API_KEY: simplest option. An API key created in the GCP console is sent as x-goog-api-key, without a token exchange.
GOOGLE_APPLICATION_CREDENTIALS: path to a supported credential JSON file.
Default ADC file: if neither of the above is set, zut checks the file written by gcloud auth application-default login. This is ~/.config/gcloud/application_default_credentials.json on Unix systems and %APPDATA%\gcloud\application_default_credentials.json on Windows.

Two credential file shapes are supported:

type: "service_account": zut signs a JWT with the private key and exchanges it for a short-lived access token.
type: "authorized_user": zut exchanges the stored client ID, client secret, and refresh token for a short-lived access token.

Access tokens are cached in memory and refreshed on demand.

If none of these are available, zut errors with vertex: no auth — set GOOGLE_CLOUD_API_KEY or GOOGLE_APPLICATION_CREDENTIALS.

Local models with ollama

zut works with ollama out of the box. Ollama serves an OpenAI-compatible API locally, so any model you have pulled works with zut.

Quick start:

ollama pull qwen3.5:4b
zut --provider ollama --model qwen3.5:4b

That's it. No API key needed for local models. zut defaults to http://localhost:11434.

For a remote ollama instance or one behind auth:

zut --provider ollama --model llama3 --base-url https://my-server.com/v1 --api-key my-token

You can also add models to your models.json so you don't need flags every time:

{
  "providers": {
    "ollama": {
      "models": [
        {
          "id": "qwen3.5:4b",
          "name": "Qwen 3.5 4B",
          "contextWindow": 32768,
          "maxTokens": 8192
        }
      ]
    }
  }
}

The ollama provider uses the OpenAI chat completions protocol internally, so it also works with any OpenAI-compatible server (vLLM, LM Studio, LocalAI, etc.).

Local models with llama.cpp router mode

zut can connect to a recent llama.cpp router, manage its GGUF files, and use loaded models through the router's OpenAI-compatible inference API. This is separate from Ollama. An Ollama server normally listens on port 11434 and should use zut's ollama provider instead.

Install or update llama.cpp. On macOS with Homebrew:

brew install llama.cpp
# or, when already installed
brew upgrade llama.cpp

Create a directory for GGUF files and start llama-server without --model, -m, or -hf. Supplying one of those options starts a single model rather than the router API zut needs.

mkdir -p ~/llama-models

llama-server \
  --models-dir ~/llama-models \
  --no-models-autoload \
  --jinja \
  --host 127.0.0.1 \
  --port 8080 \
  -ngl 999 \
  -c 32768

--no-models-autoload leaves load decisions to /llama. --jinja enables model chat templates and improves tool-call compatibility. -ngl 999 requests maximum GPU offload, while -c 32768 limits each loaded model to a 32K context. Adjust these values for your hardware.

Confirm that router mode is active before configuring zut:

curl http://127.0.0.1:8080/health
curl http://127.0.0.1:8080/models

The models request must return JSON with a data array. A 404 usually means the server is outdated, running on a different port, or was started in single-model mode.

In zut, run /login, choose api key, and select llama.cpp. Enter http://127.0.0.1:8080 as the router URL and leave the API key empty for a local-only server. Do not enter /v1; zut derives the inference URL itself. The saved URL and optional key live in $ZUT_HOME/auth.json.

You can configure the same connection through environment variables:

export LLAMA_BASE_URL=http://127.0.0.1:8080
export LLAMA_API_KEY=optional-secret

When using a key, launch the server with the matching --api-key value. Keep --host 127.0.0.1 unless remote clients must reach the router.

Run /llama to:

inspect the router's current model states
search Hugging Face for GGUF repositories
choose a quantization and download it with byte progress
explicitly load or unload a model
press d to ask the router to remove a downloaded cache model after confirmation

Models discovered through --models-dir or a preset cannot be removed by zut. Delete those files from their configured source instead. The router removes the selected GGUF from its Hugging Face cache, but some llama.cpp versions retain shared repository artifacts such as mmproj files. Remove the repository's cache directory manually if those artifacts are no longer needed. Hugging Face search uses HF_TOKEN when available. Gated repositories require prior access approval, and the llama-server process also needs an authorized HF_TOKEN because the server performs the download.

Opening /model refreshes the router and lists every loaded model under provider llama.cpp. Unloaded models are intentionally omitted because they cannot answer inference requests. Load them through /llama first, then select them through /model.

A model installed through Ollama is kept in Ollama's internal storage and is not automatically available as a llama.cpp GGUF file. Download a GGUF copy through /llama or place GGUF files in ~/llama-models, then restart the router so it discovers files added manually.

Clipboard images

In the main chat, ctrl+v checks the system clipboard for an image before falling back to text. A pasted image appears as a [clipboard image #N] marker and is attached when you submit the prompt; esc or ctrl+c clears pending image markers with the rest of the input. Wayland image paste uses wl-paste from wl-clipboard; X11 image paste uses xclip when available. Clipboard images larger than 32 MiB are ignored and use the normal text-paste fallback.

Inline images

When a tool returns an image (for example read on a PNG), zut renders it inline on terminals that support it: Ghostty, Kitty, iTerm2, WezTerm. On other terminals you see a text placeholder with MIME type, pixel dimensions, and byte size. Control with the ZUT_INLINE_IMAGES env var:

Value	Effect
unset (default)	Auto-detect based on `TERM_PROGRAM`; use the text placeholder inside VS Code and Herdr.
`iterm`, `iterm2`	Force the iTerm2 OSC 1337 protocol.
`kitty`	Force the Kitty graphics protocol.
`off`, `none`	Always use the text placeholder.

Herdr's Kitty graphics support is currently experimental, so zut does not enable inline images there automatically. After enabling experimental.kitty_graphics in Herdr, set ZUT_INLINE_IMAGES=kitty to opt in.

Frames containing images are full-repainted (no differential diff) to prevent stale image pixels from lingering through scroll. That costs one terminal flash per image-containing frame; set ZUT_INLINE_IMAGES=off if that bothers you.

Tool rendering

By default each tool call (bash, read, write, edit, create_worktree, lsp) renders inside a bordered panel — a ┌─ header ─┐, │-prefixed body rows, and a └─┘ footer. On a screen with many calls the borders can read as busy, so zut also offers a flat mode: a single quiet header line per call (▌ bash …) with indented, border-free output. Same information — tool name, arg summary, streamed output, the ... (N more lines, ctrl+o to expand) truncation — just no frame.

Set the tool_render key in $ZUT_HOME/config.json:

{
  "tool_render": "flat"
}

Value	Effect
unset / `"box"` (default)	Each tool call is wrapped in a bordered panel.
`"flat"`	Boxless: a quiet header line plus indented output.

The ZUT_FLAT_TOOLS env var overrides the config for a single run, which is handy for trying it without editing the file:

Value	Effect
`1`, `true`, `yes`, `on`, `flat`	Force flat rendering.
`0`, `false`, `no`, `off`, `box`	Force the bordered panel.
unset	Fall back to the `tool_render` config key.

ZUT_FLAT_TOOLS=1 zut   # flat, just this run
ZUT_FLAT_TOOLS=0 zut   # boxes, even if config.json says "flat"

Either way, theme colors still drive the rendering (the header uses your accent/foreground, output uses the tool-output color) and ctrl+o still expands a truncated result.

Tool arg width

The header line for a tool call shows the tool name plus a one-line summary of its primary argument — a path, a command, or a query. That summary is truncated to 60 cells by default (web_answer What is the best architecture to implement resilience wit...). On a wide terminal that can clip long queries more than you'd like, so set the ZUT_TOOL_ARG_WIDTH env var to raise (or lower) the limit:

ZUT_TOOL_ARG_WIDTH=120 zut   # allow up to 120 cells before truncating

Value	Effect
unset (default)	Truncate the arg summary at 60 cells.
integer in `[20, 500]`	Truncate at that many cells instead.
anything else	Ignored; falls back to the 60-cell default.

Compact input

By default a message you send renders as a padded, background-tinted bubble: a blank tinted row above and below the text, with a ▌ accent bar down the left. So even a one-line prompt occupies three rows. Set compact_input to collapse it to a single quiet ▌ your text gutter line per wrapped row — no padding rows, no background tint.

{
  "compact_input": true
}

Value	Effect
unset / `false` (default)	Padded, background-tinted user bubble.
`true`	One quiet gutter line per wrapped row.

The ZUT_COMPACT_INPUT env var overrides the config for a single run (1/true/on/compact force compact; 0/false/off/bubble force the bubble):

ZUT_COMPACT_INPUT=1 zut   # compact, just this run

Queued messages

You can keep typing while the agent is working. Pressing enter during a turn queues the message instead of interrupting: it shows up above the status bar as sliding in: <text> and is delivered as the next user turn the moment the current one finishes. Queue as many as you want; they run in order. esc cancels the active turn and drops the queue so a runaway turn doesn't flood you with stale follow-ups; ctrl+c while busy arms the exit hint instead of interrupting, a second ctrl+c within two seconds exits zut.

To recover the most recently queued message back into the editor (to tweak it before it runs), press Option+↑. In VS Code's integrated terminal that chord doesn't survive xterm.js's macOS key handling — use Option+Shift+↑ there. zut's hint line under the sliding-in queue adapts automatically based on $TERM_PROGRAM.

Slash commands also work while the agent is busy. Non-destructive ones (/help, /jump, /btw, /sessions, /skills, /reasoning, /settings, /jail, /unjail, /exit) take effect immediately. Destructive ones (/clear, /compact, /login, /logout, /model, /reload-ext) cancel the active turn first and then run.

Keys (interactive mode)

Input

Key	Action
`enter`	Submit (queued if the agent is busy).
`alt+enter`	Newline.
`tab`	Complete the selected slash command.
`esc`	Cancel the current turn (while busy); clear input (while idle). Two parsed bare `Esc` presses within 500 ms open `/session tree` only when the editor is idle and empty; dialogs, busy/queued work, and modified keys keep their existing precedence.
`ctrl+c`	Clear the input and queue (while idle) or arm the exit hint (while busy). Press again within 2s to exit. Use `esc` to cancel a running turn.
`ctrl+d`	Exit on empty input.
`ctrl+b`	Toggle the right sidebar; hidden or narrow widgets use a bounded above-input fallback.
`ctrl+l`	Redraw the screen.
`ctrl+v`	Paste clipboard text into the focused chat, side chat, dialog, filter, or credential input. In the main chat, image clipboard content is attached to the next prompt when the platform exposes it (macOS pasteboard, Wayland `wl-paste`, or X11 `xclip`). On Linux, text uses `wl-paste`, `xclip`, or `xsel`; terminal-native bracketed paste remains available without those commands.
`ctrl+o`	Expand or collapse long tool results (read, write, edit, bash, create_worktree, lsp, and web_search outputs over ~12 lines).
`ctrl+1` ... `ctrl+9`	Switch to the model bound to that quick-model slot (configured in `/settings` -> model shortcuts). No-op while a turn is running.
`@`	Open the file picker. Browse files and directories in the working directory.

File picker (`@`)

Key	Action
`@`	Open the file picker (type after a space or at the start of input).
`up`, `down`	Navigate the file list.
`right`	Open the selected directory.
`left`	Go back to the parent directory.
`enter`	Select the file or directory and insert it as a chip (`[file:name]` or `[dir:name/]`).
`esc`	Close the file picker.

Type @ followed by a filter string to narrow the list (e.g. @read shows only entries containing "read"). Selected files are inserted as compact chips that expand to the full path on submit. Dragged-and-dropped files and directories also collapse to chips automatically.

Key	Action
`ctrl+a`, `ctrl+e`	Jump to start or end of line.
`alt+left`, `alt+right`	Jump one word back or forward.
`ctrl+u`, `ctrl+k`	Delete to start or end of line.
`ctrl+w`, `alt+backspace`	Delete the previous word.
`up`, `down`	Move within multi-line input. At the top edge, `up` recalls previous prompts and `down` moves forward through prompt history.

Chat scroll

Key	Action
`pgup`, `pgdn`	Scroll one page up or down.
`up`, `down` (editor empty, not browsing prompt history)	Scroll three lines up or down. This is how the mouse wheel reaches the scroll logic on most terminals.

Extensions

zut can be extended in any language via a subprocess + JSON-RPC protocol. Extensions can register slash commands, expose tools to the model, intercept tool calls (block or rewrite args), gate whole turns before the model is called, and rewrite the assistant's visible text before it reaches the user. None are installed by default; opt in explicitly. Hot-reload any time with /reload-ext.

Install and manage

zut ext install <path|git-url>   # copy / clone into $ZUT_HOME/extensions/
zut ext install --build=go <path> # explicitly build and install local Go source
zut ext list                      # show installed extensions
zut ext doctor                    # diagnose load, registration, and conflict issues
zut ext logs <name> [-f]          # cat or tail the extension's stderr log
zut ext enable <name>             # re-enable a disabled extension
zut ext disable <name>            # disable without removing
zut ext remove <name>             # delete an extension directory

For local installs, zut validates extension.json and any executable path relative to the extension directory before reporting success. It never runs a build implicitly. Use zut ext install --build=go <path> to explicitly build a local Go extension; other source-based extensions must provide their runtime artifact or launcher themselves. A failed validation or build leaves no partial installation behind.

zut ext doctor keeps normal extension startup fail-soft, but gives you an explicit troubleshooting view: manifest errors, disabled or shadowed extensions, subprocess load errors, ready/auto-ready status, registered commands/tools, registration conflicts, warnings, and the stderr log path.

For development, point zut --ext <path> at a working directory and skip the install step entirely. Repeatable; takes precedence over installed extensions of the same name.

Updating extensions

zut update refreshes the zut binary and every installed extension that lives in a git checkout. Per-extension behaviour:

Disabled extensions are skipped.
Extensions without a .git/ directory (installed by zut ext install ./local-path) are skipped — there is no remote to pull from.
For the rest, zut stashes any dirty worktree state (including untracked runtime files like todos.json or config.json), runs git pull --ff-only, and pops the stash. If the pop produces conflicts, the conflict markers are left in place and you'll see a warning.
Diverged branches, offline pulls, or any other git failure are reported as failed and the next extension is processed. zut update itself never aborts because of an extension.
zut does not run any build step (go build, npm install, make) after the pull. Extension authors are expected to commit the runnable artifact (binary, transpiled JS, etc.). If you need a build, run it explicitly, reinstall the extension, or use /reload-ext for a working-tree copy.

Theme-only extensions

An extension may ship only a theme: extension.json plus theme.json (or themes/theme.json) and no executable. zut loads it without spawning a subprocess and shows it in /settings with source information. See docs/themes.md.

Reference

examples/extensions/ ships reference implementations in Go, TypeScript, Node, and shell, including tasked-phases for spec-driven phase/checklist tracking. See docs/extensions.md for the full protocol, the SDK API (packages/agent/ext), and the phase roadmap.

Skills

A skill is a per-folder SKILL.md file with a YAML frontmatter header. zut discovers skills at startup, surfaces their names in the system prompt, and exposes a built-in skill tool the model uses to load the body on demand.

By default zut loads built-in skills plus user-installed skills from:

./.zut/skills/<name>/SKILL.md (project)
$ZUT_HOME/skills/<name>/SKILL.md (global)
./.claude/skills/<name>/SKILL.md, ~/.claude/skills/<name>/SKILL.md (Claude-compatible layout)
./.agents/skills/<name>/SKILL.md, ~/.agents/skills/<name>/SKILL.md (agent-compatible layout)

User skill roots are scanned recursively. A nested skill keeps its frontmatter name and can also be loaded by its slash-separated path relative to the skill root, such as systems-backend/subskills/golang-patterns.

See docs/skills.md for the frontmatter fields, authoring tips, and example skills under examples/skills/.

Telegram bot (bridge)

zut can run as a telegram bot so you can DM it from your phone. Two ways to run it: from inside the TUI (the running session mirrors into Telegram) or as a standalone background daemon (a headless bot with its own independent agent).

From inside the TUI

Type /telegram in the running TUI to open a picker with connect, disconnect, and status. When connected:

DMs from the paired user become prompts in the same session you're typing in, so you can continue a conversation from the terminal on your phone and back again.
Messages you type in the TUI are mirrored into the Telegram thread prefixed you: ... and the assistant's replies come back prefixed zut: ..., so the Telegram chat stays a complete record of both sides of the conversation.
Messages sent from Telegram show up as your own bubble in Telegram (no mirror) and the assistant's reply to them comes back bare (no prefix).
The status bar shows a - tg - tag while the bridge is active.
/telegram connect / /telegram disconnect / /telegram status (or /tg) also work as direct commands without the picker.

The in-TUI bridge refuses to start while the standalone daemon (below) is running, since two concurrent long-poll consumers of the same bot race on every update and silently drop messages.

Standalone daemon

For headless servers or long-running bots unattached to a TUI:

zut telegram-bot setup     # paste a BotFather token, verify, save
zut telegram-bot run       # foreground: long-poll in this terminal (ctrl+c to stop)
zut telegram-bot start     # background: detach and return immediately
zut telegram-bot stop      # SIGTERM the background bot (SIGKILL after 5s)
zut telegram-bot logs -f   # tail $ZUT_HOME/logs/bot.log (omit -f to just cat)
zut telegram-bot status    # config (token masked) + running/stopped
zut telegram-bot reset     # forget the token and paired user
# short alias: `zut tg ...` is accepted for every subcommand

The background flavor writes the child's PID to $ZUT_HOME/bot.pid and redirects stdout and stderr to $ZUT_HOME/logs/bot.log. zut telegram-bot stop reads that PID, sends SIGTERM, waits up to five seconds, then escalates to SIGKILL if the child is still alive. Running two instances at once is refused at startup.

Use the installed binary for start. go run ./cmd/zut telegram-bot start won't work. go run builds a binary in a temp directory and deletes it when it exits, which kills the detached child. Run make install (or go build) first and invoke the installed binary.

Setup flow:

Talk to @BotFather on telegram, run /newbot, copy the token it gives you.
Run zut telegram-bot setup and paste the token when prompted.
Run zut telegram-bot run in the directory you want the agent to operate in.
Open your bot on telegram, send /start. The first user to do this claims the bridge (stored as allowed_user_id); every other user is rejected.

From then on, any DM you send is forwarded to the agent as a user prompt. Attached photos or image/* documents are downloaded and passed to vision-capable models. In-bot telegram commands are case-insensitive: /help, /status, /stop (cancel the current turn). Config lives in $ZUT_HOME/bot.json (mode 0600).

Starting either Telegram bridge removes any webhook configured for that bot before long polling begins, while preserving pending updates. Telegram does not allow webhooks and getUpdates polling at the same time, so do not share the bot token with another service that expects to keep a webhook active.

Bot mode respects the usual zut flags: --provider, --model, --cwd, --reasoning, --continue, --no-session, --no-tools, and so on. Run zut tg run -c --model claude-opus-4-1 to resume the latest session on Opus, for example.

Architecture: protocol-agnostic bot core

The messenger functionality is split in two layers. A generic, protocol-agnostic core lives in packages/agent/modes/bot: it owns the turn queue, agent prompting, built-in command dispatch (/start, /help, /status, /stop), status formatting, and per-turn credential refresh. Concrete transports implement the small BotAdapter interface (inbound polling, sending replies, a typing indicator, and optional protocol-specific status text); the Telegram support in packages/agent/modes/telegram is one such adapter.

This means additional messaging backends (Discord, Slack, Signal, and similar) can be added by implementing BotAdapter in a new package and wiring up a subcommand. No changes to the runner, agent, or core are required. Channel IDs are opaque strings owned by the adapter, so the shared runner stays free of protocol-specific types.

Development

make help      # list the important developer commands
make build     # build ./bin/zut as 0.0.0-dev
make test      # go test -race ./...
make test-fast # go test ./...
make lint      # golangci-lint + go vet + gofmt check
make lint-install # install the pinned golangci-lint version
make fmt       # gofmt -w .
make install   # install the current checkout with go install
make go-install # install the latest published module version
make release VERSION=0.1.0 # cross-compile release binaries

Source layout (single Go module, four packages under packages/):

cmd/zut/                              main()
packages/provider/                    LLM client surface, model catalog, streaming clients
packages/provider/auth/               credential store, api-key probe, oauth, login server
packages/core/                        agent loop, sessions, cost tracking, compaction
packages/tui/                         terminal raw-mode, input parser, editor, renderer, markdown, view
packages/agent/                       cli wiring, arg parsing, system prompt, config
packages/agent/lsp/                    LSP clients, server discovery, linters, diagnostics
packages/agent/extensions/            extension subprocess manager
packages/agent/extproto/              extension wire-format types
packages/agent/modes/                 interactive tui, print, json, dialogs
packages/agent/modes/bot/             protocol-agnostic bot runner (BotAdapter interface)
packages/agent/modes/telegram/        telegram adapter, api client, daemon
packages/agent/tools/                 read, write, edit, bash, create_worktree, lsp, web search, sandbox
packages/agent/skills/                skill discovery, frontmatter parser, skill tool
packages/agent/subagents/             named profiles, supervisor, and background runtime
packages/agent/sdk/                   public Go SDK for embedding zut in-process (package sdk)
packages/agent/ext/                   public Go SDK for writing extensions (package ext)

Downstream consumers can depend on individual packages: go get github.com/bnema/zut/packages/core pulls only core and its transitive deps (today: provider), no agent or TUI code.

License

MIT

source

1# zut
2
3> [!NOTE]
4> **Fork notice:** `zut` is an independent fork of [zot](https://github.com/patriceckhart/zot) adapted for my own workflow but feel free to use it too.
5
6## What is it?
7
8Yet another coding agent harness, lightweight and written (vibe-slopped) in go.
9
10- one static binary.
11- built-in providers for Anthropic, OpenAI/Codex/Responses, Kimi, DeepSeek, Google Gemini/Vertex, GitHub Copilot, Bedrock, Azure OpenAI, OpenRouter, Groq, Cerebras, xAI, Together, Hugging Face, Mistral, Moonshot, Z.AI, Xiaomi, MiniMax, Fireworks, Vercel AI Gateway, OpenCode, Cloudflare AI, and Ollama/local models.
12- seven core built-in tools (read, write, edit, bash, create_worktree, lsp, and web_search); the conditional `skill` tool is available when skills are enabled. See [docs/web-search.md](docs/web-search.md) for web-search egress and availability boundaries.
13- three run modes (interactive tui, print, json).
14- built-in telegram bot.
15- extensions in any language via subprocess + json-rpc. None installed by default; opt in with `zut ext install` or `zut --ext`. See [docs/extensions.md](docs/extensions.md).
16- user and extension themes via JSON; see [docs/themes.md](docs/themes.md).
17- standing instructions via `AGENTS.md` files (global and per-project); see [Persistent instructions](#persistent-instructions-agentsmd).
18- reusable instructions via `SKILL.md` files; see [docs/skills.md](docs/skills.md).
19- named subagent profiles from `~/.agents/agents/*.md`; see [docs/subagents.md](docs/subagents.md).
20- portable agents from local directories, `.zut` files, or temporary public GitHub downloads; see [docs/zutfiles.md](docs/zutfiles.md).
21
22## Install
23
24### One-liner (macOS, Linux)
25
26```bash
27curl -fsSL https://raw.githubusercontent.com/bnema/zut/main/install.sh | bash
28```
29
30Detects your OS and architecture, downloads the latest release from GitHub, verifies the SHA-256 against the release's `checksums.txt`, extracts the binary, and drops it in `/usr/local/bin`, `~/.local/bin`, or `~/bin`, whichever is writable first. Pass a version or prefix to pin:
31
32```bash
33curl -fsSL https://raw.githubusercontent.com/bnema/zut/main/install.sh | bash -s -- v0.1.0 ~/bin
34```
35
36### One-liner (Windows, PowerShell)
37
38```powershell
39iwr -useb https://raw.githubusercontent.com/bnema/zut/main/install.ps1 | iex
40```
41
42Drops `zut.exe` into `$HOME\bin` and adds it to the user PATH if missing. Open a fresh terminal afterwards.
43
44### go install
45
46```bash
47go install github.com/bnema/zut/cmd/zut@latest
48```
49
50The installed binary reports the tagged module version and supports `zut update`.
51
52### From source
53
54```bash
55git clone https://github.com/bnema/zut
56cd zut
57make help         # list the important developer commands
58make build        # produces ./bin/zut (0.0.0-dev by default)
59make install      # install the current checkout with go install
60make go-install   # install the latest published module version
61```
62
63`make go-install GO_INSTALL_VERSION=v0.1.0` installs a specific published
64version. `make install` is different: it installs the current checkout as a
65development build.
66
67### Prebuilt binaries
68
69Every release on the [releases page](https://github.com/bnema/zut/releases) ships archives for Linux, macOS, and Windows on amd64 and arm64 (except windows/arm64), plus a `checksums.txt` file. Download, verify, `chmod +x`, and drop on your `$PATH`.
70
71## Authenticate
72
73The easiest way is to just run `zut` and type `/login`. The TUI opens even without credentials and walks you through a browser-based login flow.
74
75### Credential lookup order
76
771. `--api-key` flag
782. provider-specific env var (`ANTHROPIC_API_KEY`, `OPENAI_API_KEY`, `KIMI_API_KEY`, `MOONSHOT_API_KEY`, `DEEPSEEK_API_KEY`, `GEMINI_API_KEY`, `GOOGLE_API_KEY`, `GROQ_API_KEY`, `OPENROUTER_API_KEY`, `MISTRAL_API_KEY`, `XAI_API_KEY`, `CEREBRAS_API_KEY`, `TOGETHER_API_KEY`, `HF_TOKEN`, `ZAI_API_KEY`, `XIAOMI_API_KEY`, `MINIMAX_API_KEY`, `FIREWORKS_API_KEY`, `AI_GATEWAY_API_KEY`, `COPILOT_GITHUB_TOKEN`, `GITHUB_COPILOT_TOKEN`, and others for provider-specific backends)
793. `$ZUT_HOME/auth.json` (API key or OAuth token; mode 0600)
80
81`$ZUT_HOME` defaults to:
82- All platforms: `$XDG_STATE_HOME/zut` when `XDG_STATE_HOME` is set
83- macOS fallback: `~/Library/Application Support/zut`
84- Linux fallback: `~/.local/state/zut`
85- Windows fallback: `%LOCALAPPDATA%\zut`
86
87### API keys from commands
88
89To keep an API key in a password manager instead of `auth.json`, configure an `api_key_command` for the provider:
90
91```json
92{
93  "anthropic": {
94    "api_key_command": {
95      "program": "op",
96      "args": ["read", "op://Work/Anthropic/credential"],
97      "timeout_ms": 120000
98    }
99  }
100}
101```
102
103For a provider added through `models.json`, put the same credential object under `additional_api_key_creds` using its provider ID. `program` is executed directly, without a shell, so each argument must be a separate `args` entry. `timeout_ms` is optional and defaults to 120 seconds.
104
105zut runs the command only when that provider is selected, not while checking login status or refreshing model catalogs in the background. Successful output is cached in memory for the rest of the zut process and is never written to disk. The command must print one non-empty line to stdout; zut removes trailing CR/LF characters, limits output to 64 KiB, and does not include command output in errors. Saving a normal key through `/login` replaces the command configuration, and `/logout` removes it.
106
107Treat `auth.json` as executable configuration: anyone who can modify it can cause zut to run a program under your user account. zut does not interpret `!` prefixes or execute command strings through a shell.
108
109### `/login` flow
110
111Run `zut` and type `/login`. Pick one of two methods:
112
113- **API key**: a small local web server starts on `127.0.0.1:<free-port>`, your browser opens a form, you pick a provider from the full API-key provider list, paste the key, and zut saves it to `auth.json` if accepted. Providers with a lightweight model-list endpoint are probed before saving; provider backends that need extra project/account env vars are saved directly.
114- **Subscription**: use your Claude Pro/Max, ChatGPT Plus/Pro, Kimi Code, SuperGrok/X Premium, or GitHub Copilot subscription. DeepSeek and Google Gemini do **not** have a subscription login path. For those, use the API-key flow.
115  - Anthropic and OpenAI pin the browser callback to fixed provider-specific ports (`localhost:53692` for Anthropic, `localhost:1455` for OpenAI) because those are the only ports their auth servers will redirect to.
116  - Anthropic uses the Claude Code OAuth flow. Messages go to `api.anthropic.com` with a bearer token and the Claude Code identity headers.
117  - OpenAI uses the Codex CLI OAuth flow. Messages go to `chatgpt.com/backend-api/codex/responses` with the `chatgpt-account-id` extracted from the returned id_token.
118  - Kimi uses the Kimi Code device-code OAuth flow. zut opens the verification URL, polls until you approve it in the browser, then sends messages to `api.kimi.com/coding/v1` with the Kimi Code identity headers.
119  - xAI uses a device-code OAuth flow. zut opens a prefilled authorization URL, polls for approval, and uses the resulting token with the xAI API.
120  - GitHub Copilot uses GitHub's device-code login flow. zut stores the GitHub access token and exchanges it for short-lived Copilot inference tokens on demand.
121
122> **Note on subscription login.** The OAuth client IDs used are the ones published in Anthropic's Claude Code CLI, OpenAI's Codex CLI, Kimi Code CLI, xAI's device flow, and GitHub Copilot's device-code flow. Reusing them from a third-party tool may be against their terms of service and may be revoked at any time. Use it at your own risk; the API-key flow is the safe default.
123
124### Token refresh
125
126OAuth access tokens are short-lived (Anthropic ~8h, OpenAI ~30d; Kimi, xAI, and GitHub Copilot also use refresh/exchange flows). zut refreshes or exchanges them automatically:
127
128- At every credential lookup, zut checks the stored `expiry` and, if past it (with a 60s safety margin), hits the provider's `oauth/token` endpoint with the stored `refresh_token`, persists the new `access_token`, `refresh_token`, and `expiry` back to `auth.json`, and hands the fresh token to the client.
129- The telegram bridge additionally refreshes once per turn so a bot that runs for days keeps working without manual intervention.
130- If the refresh itself fails (the `refresh_token` was revoked, or the account was logged out everywhere), the error bubbles up to the caller: the TUI shows it in the status line, the bot replies with it in your DM. Run `/login` to get a fresh token pair.
131
132All data lives under `$ZUT_HOME`:
133
134```
135$ZUT_HOME/
136├── config.json         # last-used provider/model/theme and persistent settings
137├── auth.json           # api keys and oauth tokens (mode 0600)
138├── sessions/           # jsonl transcripts, one dir per cwd
139├── models-cache.json   # live /v1/models discovery cache (6h ttl)
140├── AGENTS.md           # optional: global instructions appended to the prompt
141├── SYSTEM.md           # optional: replaces the built-in identity; addenda remain
142├── skills/             # optional: user SKILL.md files
143├── themes/             # optional: user theme JSON files
144├── extensions/         # installed extensions, one dir per extension
145└── logs/               # app log files
146```
147
148Drop a `SYSTEM.md` in `$ZUT_HOME` to replace the built-in identity for every run. Existing append addenda, including `AGENTS.md`, skills, and enabled Ponytail coding mode, remain layered on top. `--system-prompt` wins per invocation unless a selected replace-mode subagent profile supplies the child's identity. Delete the file to revert to the default identity.
149
150Ponytail coding mode is enabled by default, including when an existing `config.json` does not contain a `ponytail_enabled` field. When disabled, its compact guidance is omitted from resolved system prompts; when enabled, the guidance tells the model to apply itself only to engineering work. The setting persists its explicit on/off choice in `$ZUT_HOME/config.json` and can be changed from `/settings`. It is advisory guidance only: it does not change tool permissions, confirmations, jail behavior, or sandboxing.
151
152A selected subagent profile with `systemPromptMode: replace` supplies the child's base identity even when `--system-prompt` was provided for the parent run. Global append addenda, including enabled Ponytail guidance, still follow their normal inclusion rules.
153
154## Persistent instructions (AGENTS.md)
155
156Use `AGENTS.md` to give zut standing instructions that layer **on top of** the default system prompt, without replacing it. This is the friendliest way to shape behavior (for example, taming local models that jump straight to code edits) because it adds guidance rather than taking over the base identity the way `SYSTEM.md` does.
157
158zut discovers `AGENTS.md` files automatically at startup and loads them in this order:
159
1601. `$ZUT_HOME/AGENTS.md` (global, machine-wide instructions that apply to every project).
1612. Every `AGENTS.md` from the filesystem root down to the current working directory. More specific (deeper) files may override earlier ones. This includes `~/AGENTS.md` when the working directory is inside your home directory.
162
163All discovered files are appended to the prompt in that order, so a global baseline can be refined per project. To list the active Zutfile agent, loaded context paths, extensions, and user-installed skills above the interactive transcript, enable **show loaded resources at startup** in `/settings`. The agent section appears only for `zut run`, the setting is off by default, built-in skills are omitted, and the displayed lists are not sent to the model or stored in the session transcript.
164
165For a general, non-project-specific instruction set, put your rules in `$ZUT_HOME/AGENTS.md`, for example:
166
167```markdown
168Treat questions and discussions as requests for explanation. Do not edit files or run tools unless explicitly asked to make a change. Ask before modifying code.
169```
170
171`AGENTS.md` vs the other mechanisms:
172
173| Mechanism | Scope | Effect |
174|---|---|---|
175| `$ZUT_HOME/AGENTS.md` | global, every run | appended to the default prompt |
176| `./AGENTS.md` (and parent dirs) | project | appended to the default prompt |
177| `$ZUT_HOME/SYSTEM.md` | global, every run | replaces the built-in identity; append addenda remain |
178| `--append-system-prompt <text>` | single run | appends for one invocation (repeatable) |
179| `--system-prompt <text>` | single run | replaces the built-in identity for one invocation; append addenda remain |
180
181> **Note:** zut does not read a `CLAUDE.md` instruction file. The only Claude-compatible thing it picks up is skills under `.claude/skills/`. If you are migrating from Claude Code, move that content into `AGENTS.md` (global or per-project) and zut will use it.
182
183## Changelog on update
184
185The first time you launch a newer zut binary, the TUI shows the GitHub release notes once in a dismissible overlay. Press any key to close. The version is recorded in `config.json`'s `last_changelog_shown` so the same release notes never reappear. Fresh installs don't see a changelog (no upgrade has happened yet). Development builds (`0.0.0-dev`) skip both the update and changelog requests and print `dev version detected; skipping update check`. For release builds, the fetch is best-effort: a network failure or a missing release page silently skips, with another attempt on the next launch.
186
187## Usage
188
189```bash
190zut                              # interactive tui
191zut "fix the failing test"       # tui, pre-filled prompt
192zut -p "list all go files"       # print final text, exit
193zut -p --stats stats.json "task" # print final text and write generation stats
194zut --json "refactor main.go"    # newline-delimited json events, exit
195zut --continue                   # resume the most recent session for this cwd
196zut --resume                     # pick a session to resume
197zut --list-models                # show supported models
198zut --help
199```
200
201Print-mode stats contain `provider`, `model`, `prompt_tokens`, `reasoning_tokens`, `generated_output_tokens`, and `elapsed_ms`. Counts cover all model turns triggered by the prompt, including tool loops. Prompt tokens include cache reads and writes. `reasoning_tokens` is `null` when the provider does not report a separate count; in that case `generated_output_tokens` is the provider's total output count and may include reasoning. Elapsed time covers the agent run, not startup and credential resolution. The file is written only after a successful run.
202
203## Flags
204
205| Flag | Description |
206|---|---|
207| `--provider <id>` | Pick the provider (for example `anthropic`, `openai`, `openai-codex`, `kimi`, `google`, `github-copilot`, `groq`, `openrouter`, `amazon-bedrock`, `ollama`; see Providers). |
208| `--model <id>` | Pick the model (see `--list-models`). |
209| `--api-key <key>` | Override the API key. |
210| `--base-url <url>` | Override the provider base URL (tests, self-hosted). |
211| `--insecure` | Skip TLS certificate verification for the explicit `--base-url` endpoint or a `baseUrl` defined for a user model in `models.json` (self-signed local/internal inference servers). Built-in providers, auth, and model discovery keep normal TLS verification. |
212| `--system-prompt <text>` | Replace the default system prompt for this run (also overrides `$ZUT_HOME/SYSTEM.md`). |
213| `--append-system-prompt <text>` | Append text to the system prompt (repeatable). |
214| `--reasoning off\|minimum\|low\|medium\|high\|xhigh\|max` | Set the reasoning level on supported models (default: off). `max` is a separate opt-in tier above `xhigh`. |
215| `--stats <path>` | With `-p`/`--print`, write generation statistics as JSON. |
216| `-c`, `--continue` | Resume the latest session for this cwd. |
217| `-r`, `--resume` | Pick a session to resume. |
218| `--session <path>` | Resume a specific session file. |
219| `--no-session` | Don't read or write session files. |
220| `--cwd <path>` | Use `<path>` as the working directory. |
221| `--no-tools` | Disable all tools. |
222| `--no-lsp` | Disable the built-in LSP/linter tool for this run. |
223| `--tools <csv>` | Only enable the listed tools. Include `lsp` to select it explicitly. An explicit list must include `web_search` to retain or opt into web search for that invocation; explicitly including it overrides the persisted web-search setting for that invocation. |
224| `--max-steps <n>` | Cap agent loop iterations (default 50). |
225| `-e`, `--ext <path>` | Load an extension from `<path>` for this run (repeatable; wins against installed extensions of the same name). |
226| `--no-ext` | Skip extension discovery for this run. `--ext` still works on top, so `--no-ext --ext ./x` runs only `x`. |
227| `--no-skill` | Disable all skills, including built-ins. No `skill` tool is registered and the system prompt has no skill manifest. |
228| `--no-yolo` | Confirm every tool call before it runs (interactive TUI only). A dialog shows the tool name and a one-line preview of its args, while edit calls show the proposed diff in the tool panel, with four choices: yes, yes-always-this-tool-this-session, yes-always-this-session, no. Press `/` while the dialog is focused to run a slash command first; closing its input or child dialog returns to the pending confirmation. Ignored with a stderr warning in print / json / rpc modes, where tools still run freely so scripts and automation keep working. |
229
230## Tools
231
232- `read`: read text files, or inline images (PNG, JPEG, GIF, WebP).
233- `write`: create or overwrite files, making parent directories as needed.
234- `edit`: one or more exact-match replacements in an existing file.
235- `bash`: run a command in the session cwd with merged stdout/stderr and a timeout. On Unix, zut uses `/bin/bash -c` when available, then `bash -c` from `PATH`, and falls back to POSIX `/bin/sh -c` when Bash is unavailable. On Windows, it uses `cmd /C`. macOS ships Bash 3.2 by default, so newer Bash features may be unavailable.
236- `create_worktree`: create a new branch from the current `HEAD` and check it out persistently. A repository with no configured root and no `.worktrees` directory first returns bootstrap guidance without making changes; the agent asks whether to use the repository default or an external root, then retries with `bootstrap_root`. The choice is saved privately in local Git config. Choosing `.worktrees` creates `<repository-root>/.worktrees/<branch>` and adds `/.worktrees/` to the root `.gitignore`; an absolute external root leaves tracked repository files and the root `.gitignore` unchanged. The tool never copies uncommitted or ignored files, and it refuses an existing branch or worktree path.
237- `lsp`: query configured language servers and linters for diagnostics, definitions, references, hover information, symbols, renames, code actions, capabilities, and raw protocol requests. LSP servers use stdio JSON-RPC; project `lsp.json` files can add or override servers and CLI linters. Diagnostics are bounded, sorted, deduplicated by path/severity/code/start position, and repeated issues are grouped before they reach the model. See [docs/lsp.md](docs/lsp.md).
238- `web_search`: search the public web through DuckDuckGo HTML and return bounded source titles, URLs, and snippets. Enabled by default for normal CLI sessions; it is unavailable to bot, default SDK, and packaged-agent runs. See [docs/web-search.md](docs/web-search.md).
239
240When the sandbox is on (see `/jail`), filesystem tools and LSP workspace edits refuse paths outside the session cwd. `create_worktree` also requires its repository root, configured worktree destination, optional `.gitignore`, and Git metadata to remain inside the jail. Jail does not sandbox web-search network egress.
241
242## Modes
243
244- **Interactive** (default): chat TUI with streaming output, spinner, cost meter, slash commands.
245- **Print**: `zut -p "prompt"` runs the agent to completion and writes only the final assistant text to stdout.
246- **Stream**: `zut --stream "prompt"` runs without the TUI and writes assistant text to stdout as it arrives. Tool activity goes to stderr.
247- **JSON**: `zut --json "prompt"` emits one JSON object per agent event to stdout, newline-delimited. The schema is documented in [docs/rpc.md](docs/rpc.md).
248- **RPC**: `zut rpc` runs as a long-lived child process; commands in on stdin, events and responses out on stdout, both as NDJSON. Designed for embedding zut in third-party apps written in any language. See [docs/rpc.md](docs/rpc.md) for the wire schema and `examples/rpc/{python,node,shell,go}` for working clients.
249
250When an initial print, stream, or JSON request exceeds the provider context window, zut compacts the existing transcript and continues the already-appended prompt once. Print still writes only the recovered final text, stream keeps assistant text on stdout and tool diagnostics on stderr, and JSON suppresses the recoverable first terminal error so stdout remains JSONL for the successful turn. A compaction failure or a second context-window error remains terminal; this is not a general autonomous-follow-up policy. The same one-shot recovery applies to subagent workers. It does not apply to RPC, SDK, bot, or Telegram requests.
251
252## zutfile agents
253
254A zutfile packages an agent's instructions, skills, requirements, and enforced tool permissions as a shareable agent. Run one from a local directory, a packed `.zut` artifact, a short name, or directly from a public GitHub repository:
255
256```bash
257zut run ./my-agent
258zut run ./my-agent.zut
259zut run frkr/zot-archify
260zut run acme/agents/code-reviewer --cwd /path/to/project
261```
262
263Single-part names resolve only to a matching local directory or `.zut` archive. Anyone can publish an agent as a public GitHub repository and run it as `owner/repository`, or publish a collection and run an agent directory as `owner/repository/agent`. zut has no built-in owner, official collection, configured registry, or allowlist. For GitHub sources, zut downloads the repository archive into a temporary directory, validates and runs the selected agent, then removes the downloaded source when the command exits. Agent data, consent receipts, and sessions still persist under `$ZUT_HOME`. See [docs/zutfiles.md](docs/zutfiles.md) for authoring, permissions, packaging, and current limitations.
264
265## Embedding
266
267Two ways to drive zut from another program:
268
269- **Go in-process**: import `github.com/bnema/zut/packages/agent/sdk`. One `Runtime` per project; `Prompt(ctx, text, images)` returns a channel of `Event`. Small example in `examples/sdk/`.
270- **Any language, out-of-process**: spawn `zut rpc` as a subprocess and exchange newline-delimited JSON over its stdin/stdout. Wire format and event schema in [docs/rpc.md](docs/rpc.md). Reference clients live under `examples/rpc/`.
271
272Both interfaces share the same event schema, so transcripts captured by one can be replayed through the other.
273
274## Slash commands
275
276Slash command names are case-insensitive in the TUI and messaging backends; arguments keep their original case. Type `/` in the TUI to open the autocomplete popup. Available commands:
277
278| Command | Description |
279|---|---|
280| `/help` | Show key bindings and commands. |
281| `/login` | Log in via API key or subscription (opens a dialog). |
282| `/logout [provider]` | Clear credentials for any logged-in provider, or all when omitted. `/logout openai-codex` clears ChatGPT/Codex subscription auth while preserving a public OpenAI API key; `/logout kimi` also disables fallback to the official Kimi Code CLI token until you log in to Kimi through zut again. |
283| `/model` | Pick a model from a list (or `/model <id>` to set directly). |
284| `/reasoning` | Set the reasoning level for subsequent model calls. |
285| `/fast` | Toggle fast mode for subsequent model calls. |
286| `/llama` | Connect to the configured llama.cpp router, load, unload, or remove cached models, and search/download GGUF models from Hugging Face with live progress. Shown after llama.cpp login is configured. |
287| `/sessions` | Resume a previous session for this directory. The picker omits branches created only for tree navigation. |
288| `/fork` | Pick a previous user message and fork the current session after that turn. The selected turn becomes branch context and no provider turn starts during the checkout. |
289| `/session` | Four ops on the current session: `export` to a portable `.zutsession` file, `import` one back in, `fork` from a past user message into a new branch, `tree` to switch between branches. Opens a picker without an argument; direct forms: `/session export [path]`, `/session import <path>`, `/session fork`, `/session tree`. Default export destination is `~/Downloads`. `Esc` `Esc` from an idle, empty editor is a shortcut for `/session tree` when the terminal supplies two parsed bare Escape events. |
290| `/jump` | Scroll the chat to a previous turn (or `/jump <text>` to filter). |
291| `/btw` | Side chat with full context that doesn't add to the main thread. |
292| `/subagents` | Spawn, monitor, and chat with background subagents. Each is a separate long-lived process with bounded lifecycle state, structured results, and optional Git worktree isolation. Named profiles can be selected with `agent`; see [docs/subagents.md](docs/subagents.md). |
293| `/skills` | List discovered skills (SKILL.md files) and preview their bodies. |
294| `/compact` | Summarize the transcript into one message to free up context. |
295| `/study` | Run the canned prompt "Read and understand everything in the current directory." so the agent has full project context before you start asking targeted questions. Pass a path — typed, drag-dropped, or selected via `@` — to target a specific file or directory instead: `/study [dir:packages/]`, `/study cmd/zut/main.go`. |
296| `/jail` | Confine tools to the current directory. |
297| `/unjail` | Allow tools to touch paths outside again. |
298| `/reload-ext` | Hot-reload all extensions (re-read manifests, respawn subprocesses, rebuild tool registry). |
299| `/telegram` | Connect, disconnect, or show status of the Telegram bridge (takes `connect` / `disconnect` / `status` as an optional argument; opens a picker without one). When connected, DMs from the paired user become prompts in the running session and the assistant's replies are mirrored back to Telegram. Alias: `/tg`. |
300| `/settings` | Change persistent settings, including web search, inline images, terminal alerts, AI terminal titles, auto-subagents, Ponytail coding mode, fast mode, main/sub-agent LSP access, and the auto-compact threshold. `/fast` is a shortcut for the fast-mode toggle. Saved to `$ZUT_HOME/config.json`; setting changes apply without a restart, while AI title generation waits for the first real prompt. |
301| `/clear` | Clear the chat transcript. |
302| `/exit` | Exit zut. |
303
304Extension-registered commands appear under a divider at the bottom of the popup, sorted by name.
305
306### Shell escape (`!command`)
307
308Type `!` followed by a command to run it directly without going through the model. Everything after the `!` is passed to the same shell the `bash` tool uses (`/bin/bash -c` when available on Unix, then `bash -c` from `PATH`, with POSIX `/bin/sh -c` as a fallback; `cmd /C` on Windows), runs in the session working directory, and honors the `/jail` sandbox. The command, merged output, and exit status are appended to the transcript as user context, so the model can use them on the next turn. Running the command does not itself start a model turn. A running `!command` shares the busy state with the agent: `esc` cancels it, and you cannot start one while a turn (or another shell escape) is in flight.
309
310### `/sessions`
311
312Shows previous sessions for the current working directory, newest first, with timestamp, model, message count, cost, and the session title. Session entries load in the background and are revealed incrementally in newest-first order; an older result may wait briefly for entries ahead of it so the list never reorders, while the picker keeps showing progress for the remaining entries. Once an entry appears, `up`/`down` and `enter` can select it immediately; `esc` cancels and closes the picker. zut swaps the current session file for the selected one and replays the full transcript (including tool calls) into the agent. Sessions remember their stored provider and model: resuming rebuilds the live agent when necessary instead of silently using a different model; if that rebuild fails, the current session is left unchanged. Branches created for tree navigation remain available to `/session tree` but are hidden from this flat picker. A fresh interactive session asks the active model for a concise title after the first real prompt and restores that title when resumed.
313
314### `/session`
315
316Four ops on the current session. `/session` alone opens a picker; each is also runnable directly.
317
318- **`/session export [path]`**. Writes the running transcript to a portable `.zutsession` file. Default destination is `~/Downloads/<timestamp>-<session-id>-<prompt-slug>.zutsession`. Pass a path to override; a directory is fine (a dated name is built inside), a bare name gets `.zutsession` appended. The meta's cwd is stripped on the way out so the recipient doesn't see your filesystem layout.
319
320  **What's included.** Only the main chat thread of the running session — messages, tool calls, tool results, compactions, and usage. **`/subagents` subagents are NOT included.** Their transcripts, unix-socket inboxes, and per-agent session files are all machine-local; a `.zutsession` is just a chat transcript and has no way to revive a unix socket on another box. If you want the conversation, copy it out of the dashboard manually.
321- **`/session import <path>`**. Copies a `.zutsession` file into `$ZUT_HOME/sessions/<cwd-hash>/` with a fresh id and the current cwd, then switches the running agent onto it. Imported sessions are first-class: they show up in `/sessions` and `/jump`, and in the current-family tree when they are part of that family. Drag-drop paths in the editor are accepted (zut strips the surrounding quotes automatically).
322- **`/fork`** (also available as **`/session fork`**). Opens a turn picker (same shape as `/jump`). Pick any past user message; zut copies the transcript through that turn into a new branch and switches to it without starting a provider request. The parent session stays on disk. Use it to try a different question without polluting the original transcript, or to rewind after the agent went down the wrong path. Use a user-message row in `/session tree` when you want the prompt restored for editing, including image attachments.
323- **`/session tree`**. Shows the current session's family: its root ancestor and descendants, not unrelated root sessions in the same cwd. Use `up`/`down` and `enter` to choose a row; `esc` closes the tree. The picker keeps pre-compaction history available as forkable user and assistant messages, while hiding tool calls, tool results, compaction checkpoints, shell/image helper rows, and other internal context. Message rows are indented at their branch points and the current endpoint is tagged `[current]`. Empty and detached branch points are represented by visible boundary rows. A child whose historical fork point no longer matches after compaction stays discoverable as a detached branch under the parent's current tail rather than disappearing. Parentless sessions are roots; orphaned children (whose parent file was deleted) remain roots.
324
325  Selecting a user-message row creates a navigation branch before that message and restores the complete editable draft, including text blocks and image attachments; no provider request is made until you submit it. Selecting an assistant-message row checks out a safe message boundary, and selecting an empty or detached boundary checks out that branch point with an empty editor. Navigation branches are hidden from `/sessions` but remain in the tree.
326
327  `/session tree` and the double-Escape shortcut use the same checks: a complete current session family must be readable, and no turn, shell escape, compaction, startup/session load, dialog, picker, suggestion, or queued message may be active. The shortcut is two parsed, unmodified bare `Esc` events within 500 ms from an idle editor with no visible text or pending image. Dialogs, confirmations, panels, pickers, and suggestions keep their existing Escape behavior; busy Escape still cancels, modified Escape is not part of the gesture, and any intervening key or timeout resets it. The shortcut depends on the terminal input path producing those parsed events; `/session tree` is the explicit equivalent when it is unavailable.
328
329### `/jump`
330
331Opens a turn picker for the current session, one row per user prompt, each showing the turn number, how many tools that turn invoked, and the first line of the prompt. `up`/`down` to pick, `enter` to jump, `esc` to cancel. Any printable rune while the picker is open extends a filter; backspace narrows it back. `/jump <text>` pre-applies the filter; if exactly one turn matches, zut jumps straight there without showing the picker.
332
333Jumping is non-destructive. The transcript is untouched, the viewport just scrolls so the chosen turn is at the top. A muted line at the top of the chat reads `viewing turn N of M, pgdn to catch up`. Scroll back to the bottom with `pgdn` (or keep scrolling with the arrow keys) and the indicator goes away.
334
335### `/btw`
336
337Opens a side-chat overlay with the full main session as frozen context, so you can ask quick clarifying questions ("does asyncio.gather() catch exceptions?", "btw the bundle budget is 10MB", "what's the default fetch timeout?") without bloating the main thread.
338
339Each question runs an isolated agent turn against `system + main transcript + side-chat history so far`. The side chat has the same tools and guards as the main chat, including per-tool confirmation when `--no-yolo` is active. Responses, tool calls, and tool results stay in the overlay. When you press `esc` to close, **nothing** has been added to the main session and subsequent main-thread turns don't re-read any of the side-chat exchanges, keeping the running context window lean.
340
341```
342/btw                              # open the overlay, type questions interactively
343/btw does PUT replace the whole resource?
344```
345
346Inside the overlay: `enter` sends, `esc` cancels an in-flight call (or closes the overlay if idle), `ctrl+c` closes immediately. Side-chat exchanges never touch the transcript and aren't persisted to the session file.
347
348### `/subagents`
349
350Background subagents that run alongside your main session. Each one is a separate `zut` subprocess with its own model loop, persistent session file, versioned JSONL control protocol, structured turn result, and lifecycle state. Shared checkout mode preserves the historical behavior; worktree mode creates a temporary detached Git worktree, captures a patch and changed-file list, and never merges automatically.
351
352> **Choose the workspace deliberately.** Use `isolation:"worktree"` for parallel coding so children cannot edit the host checkout. Use shared mode for read-only review or explicitly coordinated work. Worktree isolation is an accident-prevention guardrail, not a security sandbox.
353
354```text
355/subagents                                      # open the dashboard
356/subagents new <task>                           # spawn an agent (shared mode)
357/subagents new --agent reviewer <task>          # use a named markdown profile
358/subagents new --reasoning high <task>          # set child reasoning
359/subagents logs <id>                            # open one agent's transcript
360/subagents send <id> <text>                     # send a follow-up turn
361/subagents result <id>                          # show the structured result reference
362/subagents resume-session <id>                  # continue without replaying the task
363/subagents restart-task <id>                   # intentionally run the stored task again
364/subagents kill <id>                            # cancel gracefully, then force-stop
365/subagents remove <id>                          # delete durable state
366```
367
368**Dashboard (`/subagents` with no arg)** — a list of every agent for the current session, with process/turn state, queue position, age, workspace mode, and current activity. Keys:
369
370| Key | Action |
371|---|---|
372| `↑` / `↓` | Move cursor between rows. |
373| `enter` | Open the highlighted agent's transcript view. |
374| `n` | Spawn a new agent (opens an inline task editor; inherits the host's current model). |
375| `p` | One-off prompt editor for the selected row (without entering the transcript). |
376| `R` | Resume a stopped agent in place. |
377| `k` | Kill the selected running agent. Its session and state stay so you can resume it later. |
378| `r` | Remove the selected agent entirely (session + meta gone). |
379| `esc` | Close the dashboard. |
380
381**Inside an agent's transcript** — a chat overlay with an always-on inline composer at the bottom. The conversation flows above it; type and `enter` to send a follow-up. The view auto-follows streaming output and shows an inline spinner with the agent's current activity (`thinking`, `tool: edit_file`, etc.) while it's busy. `esc` returns to the dashboard.
382
383**Switching the spawn model from inside the editor** — while composing a task in the `n`-prompt, type `/model` on its own line and `enter`. The standard `/model` picker pops up; pick a model, the picker closes, and the editor reopens with your typed task intact and the new model pinned for the spawn.
384
385**Session scoping** — each agent is stamped with the host session that spawned it and only shows up in that session's dashboard. Swap sessions with `/sessions` and the dashboard re-narrows accordingly. Agents from other sessions keep running in the background and reappear when you switch back.
386
387**Persistence across zut restarts** — every spawn writes a durable manifest, lifecycle summary, append-only event log, session file, and structured `result.json` under `$ZUT_HOME/subagents/agents/<id>/`. On the next `zut` launch the compact summary restores each agent as **detached** without replaying its full history. Open its transcript to hydrate the durable event log, then use `R` or `/subagents resume-session <id>` to continue the existing session. `/subagents restart-task <id>` is the explicit operation that intentionally replays the stored task.
388
389**Where state lives** — per-agent manifests, session files, events, results, and patches live under `$ZUT_HOME/subagents/agents/<id>/`; inbox sockets are runtime-only and permission-restricted. Shared-mode edits land directly in the repo. Worktree-mode edits are captured as durable patches and changed-file summaries before cleanup.
390
391**`/session export` does NOT bundle subagents.** A `.zutsession` is just the main chat transcript; per-agent state (session file, unix-socket inbox) is machine-local and doesn't round-trip through a JSONL file. To share what an agent said, copy it out of the transcript view manually.
392
393**Auto-subagents.** With `/settings` -> auto-subagents on, the main agent gets the canonical `subagent_spawn` tool and a system-prompt nudge to delegate independent work. The companion `subagent_status` tool accepts an optional `agent_id`: omit it to list visible workers, or pass a full id / unique prefix to query one without waiting for completion. It returns privacy-safe JSON metadata with the worker id, lifecycle state (`starting`, `running`, `completed`, `failed`, `cancelled`, or `detached`), underlying process/turn state, timestamps, a bounded first-line task summary, and terminal-result metadata when available; it does not return prompts, transcripts, result output, credentials, provider settings, or filesystem paths. The spawn tool returns the child id and initial state immediately; completion is a durable `turn.result` with a `subagent://<id>/result` reference. It accepts named profiles, timeout, `max_turns`, and `isolation:"shared"` or `isolation:"worktree"`. Omit `max_turns` to use the supervisor policy; the default ceiling is 3 and `subagents.max_turns` changes it. Global concurrency limits apply equally to slash commands, tool calls, and batches. Off by default; toggle from `/settings`.
394
395### Named subagent profiles
396
397zut discovers the common markdown/frontmatter profile layout from `~/.agents/agents/*.md` by default. With auto-subagents enabled, the main agent receives `[subagents_list]` metadata and can select a named profile through `subagent_spawn`. Profile bodies are applied only to the selected child. See [docs/subagents.md](docs/subagents.md) for discovery, supported fields, reasoning levels, and examples.
398
399### `/settings`
400
401Opens a dialog with every persistent setting. `up`/`down` to navigate, `enter` or `space` to change the selected row, `esc` to close (rows that open a sub-view, like model shortcuts, use `esc` to go back one level first). Changes are written to `$ZUT_HOME/config.json` without a restart; individual settings document whether they affect the current turn, the next model call, or a later session event. Current settings:
402
403- **web search** — allow the normal CLI agent to send search queries to DuckDuckGo HTML and return bounded public-web sources. Enabled by default; disabling it removes `web_search` from the current interactive session and future normal CLI runs when no invocation-level tool override applies. If the current command explicitly included `--tools web_search` (alone or in its CSV list), that higher-precedence opt-in keeps web search enabled for this session and the settings row is read-only with an explanation; run zut without that explicit override to change the persisted default. The setting persists as `web_search_enabled`. Bot, default SDK, and packaged-agent runs remain unavailable regardless of this setting. See [docs/web-search.md](docs/web-search.md).
404- **render images when supported** — draw screenshots / `read`-returned images inline using the terminal's image protocol, or fall back to a text placeholder. Auto-detected from `TERM_PROGRAM`; the toggle overrides the detection. The row is greyed out and forced off on terminals that don't speak any image protocol.
405- **terminal alerts** — emit a terminal bell when the main session stops with work that may need attention, or when an extension raises a structured alert. Enabled by default; changes apply immediately and persist as `terminal_alerts_enabled`. Terminal emulators may render the bell audibly, visually, or not at all.
406- **AI terminal titles** — after the first real prompt of a fresh interactive session, make one small hidden request to the active model and set the terminal title to `zut: <title>`. The title is limited to 40 Unicode characters, persisted with the session, restored on resume, and never added to the conversation. Enabled by default; disable it to avoid the extra model request. The toggle applies immediately, but title generation still waits for the first real prompt and never starts from startup context, resumed history, or slash commands. Persists as `terminal_title_enabled`.
407- **auto-subagents** — let the main agent spawn background sub-agents in parallel via `subagent_spawn` and query live state via `subagent_status`. Off by default. The tools accept named profiles, reasoning, timeout, turn limits, and shared/worktree isolation where applicable; lifecycle and result references are persisted. Completion updates still arrive through the auto-subagents watcher. See `/subagents` and [docs/subagents.md](docs/subagents.md) for details.
408- **Ponytail coding mode** — include compact engineering guidance in each resolved system prompt; the guidance tells the model to apply it to coding, debugging, and review work rather than ordinary conversation. It favors understanding the real flow, small validated changes, reuse, and preserving safety checks. Enabled by default; changes apply to the next model call and persist as `ponytail_enabled` in `$ZUT_HOME/config.json`. It is included by interactive, print, stream, JSON, RPC, subagent, bot, SDK, and Zutfile agents.
409- **fast mode** — request the provider's fast tier where supported. It currently uses OpenAI's Fast service tier for OpenAI, OpenAI Responses, and OpenAI Codex models. Off by default; toggle it with `/fast` or `/settings`; changes apply on the next model call and persist as `fast_mode`. Other providers currently return an unsupported-provider error. Fast mode may cost more and depends on the selected model/account.
410- **lsp in main session** — enable the built-in `lsp` tool and code diagnostics for the main agent. Enabled by default; changes persist as `lsp_enabled`.
411- **lsp in sub-agents** — allow newly spawned background sub-agents to use the built-in `lsp` tool. Enabled by default; changes persist as `subagent_lsp_enabled` and apply when a child starts.
412- **auto-compact threshold** — choose `off`, `70%`, `80%`, `85%` (default), or `90%` of the model's advertised context window. The selected percentage controls automatic compaction before and after interactive turns and persists as `auto_compact_threshold`. Structural unfinished tails and truncated output continue as before. After a successful after-turn threshold compaction, zut may make at most two hidden, bounded recovery continuations when the assistant's visible text appears to promise future work; clear completed text settles normally, and a newer queued user request wins. An interrupted interactive session retains an outstanding handoff when resumed, including after portable export and import. Manual `/compact` does not silently start work. `off` disables percentage-based triggers but keeps manual `/compact` and automatic recovery from context-window and payload-too-large responses. Truncated-output continuation remains a separate priority rule.
413- **jail new sessions by default**: start every new agent with tools confined to its working directory. Off by default. The setting applies to interactive, print, JSON, RPC, and background-agent runs, persists as `jail_by_default`, and immediately updates the current interactive session. `/jail` and `/unjail` remain session-scoped overrides and do not change this default.
414- **compact transcript rendering**: reduce visual chrome in the chat transcript. Tool calls render as a quiet header plus indented output instead of a bordered box, and sent messages render without padded background bubbles. Off by default. Changes apply immediately and persist to `config.json` as `compact_mode`.
415- **show loaded resources at startup**: list the active Zutfile agent (for `zut run`), loaded `AGENTS.md` paths, extensions, and user-installed skills in compact sections above the transcript. Built-in skills are omitted. Off by default. Changes apply immediately and persist to `config.json` as `show_instructions_at_startup`.
416- **TUI settings**: opens a sub-view for input layout in display order: status, working spinner, input, then running subagents. **Input style** can be `plain` (default prompt line), `lines` (separator lines above and below the input), or `block` (a user-bubble-style input block). **Status position** places model, usage, and working-directory information above or below the input. **Working spinner position** places the busy spinner above or below the input. **Running subagent position** places live delegated-turn rows above or below the input; it defaults below the input and shows the profile or agent ID, current activity, and elapsed time since the last activity/heartbeat. On a short terminal, omitted rows collapse into one count summary so the editor remains visible. Idle, detached, and terminal turns disappear from this area immediately. Changes apply immediately and persist to `config.json` as `tui_input_style`, `tui_status_position`, `tui_working_position`, and `tui_subagent_position` (`above_input` or `below_input` for the position fields).
417- **reasoning level**: choose reasoning for supported models: off, minimum, low, medium, high, xhigh, or max. The `max` tier is opt-in and sent natively to GPT-5.6 and adaptive-thinking Claude models; unsupported backends clamp it to their highest accepted effort. The change is persisted to `config.json` and applied to the next model call. Use `/reasoning` to open this selector directly. The selector only shows distinct levels supported by the active model; models without reasoning support only offer `off`.
418- **color theme** — choose the built-in auto, inherited (from terminal), dark, or light theme, or any JSON theme discovered under `$ZUT_HOME/themes` or a loaded extension. Built-in and JSON themes follow terminal color capability: truecolor terminals receive RGB output, while RGB values fall back to xterm-256 elsewhere. Theme files can use xterm-256, ANSI, or RGB values for semantic UI colors and can also override syntax colors and spinner frames/messages. Changes apply immediately; if a selected theme file is deleted, zut resets to auto. See [docs/themes.md](docs/themes.md).
419- **model shortcuts** — opens a sub-view with nine slots (`model 1` ... `model 9`). `enter` on a slot opens the same `/model` selector and binds the chosen provider/model to that slot; `backspace` clears a slot. Once assigned, press `Ctrl+1` ... `Ctrl+9` from the editor to switch the active model instantly (the same cross-provider swap `/model` performs, transcript and cost carried over). Assigning a shortcut does not change the current model. Shortcuts are skipped while a turn is running.
420
421### `/skills`
422
423Opens a picker listing every discovered SKILL.md file, built-ins hidden. Each row shows the skill name, source, and description. `enter` opens the body inline (scrollable with `up`/`down`/`pgup`/`pgdn`); `esc` goes back. Re-runs discovery each time it opens, so edits to a SKILL.md during a session are reflected immediately.
424
425### `/compact`
426
427Sends the current transcript through the model with a structured summarization prompt. The returned summary replaces the transcript as one synthetic user message, with the last few exchanges kept verbatim for continuity. The status bar's context meter resets. Manual `/compact` only summarizes; it does not silently start work afterward. Use it when the context meter creeps past ~80%.
428
429zut also auto-compacts in the background after an interactive turn reaches the configured context threshold. Structural unfinished tails and output stopped at the model's token limit continue as before. After a successful after-turn threshold compaction, a visible assistant status that appears to promise future work may receive at most two hidden, bounded recovery continuations; clear completed text settles normally, and a newer queued user request supersedes that recovery. An interrupted interactive session resumes an outstanding hidden handoff without displaying it as a chat message. A new branch keeps that handoff only when it copies the complete effective transcript; `/fork` or `/session tree` selection at an earlier turn, and every branch from pre-compaction history, drops it and starts no hidden continuation. Manual `/compact` does not silently start work, and truncated-output continuation remains a separate priority rule. Choose `off`, `70%`, `80%`, `85%` (default), or `90%` under `/settings` → **auto-compact threshold**. You'll see `condensing history, esc to cancel` above the status bar and an `(auto)` tag next to the context percentage; `esc` aborts it without touching the transcript. Turning the percentage trigger off does not disable automatic compaction and retry after a context-window or payload-too-large response.
430
431### `/jail`
432
433Enforces a sandbox rooted at the cwd shown in the status bar. `read`, `write`, and `edit` resolve their target path (including through symlinks) and refuse anything outside the sandbox. `create_worktree` also requires its repository root, Git metadata, optional `.gitignore`, and configured worktree destination to be inside the sandbox. `bash` refuses obvious escape patterns (`sudo`, `rm -rf /`, leading `cd /`, `cd ..`, `cd ~`, `chmod -R`, `dd of=/`, and similar) and rejects shell arguments or redirections that point outside the sandbox. The status bar shows `jailed, ~/your/cwd` while active. Enable **jail new sessions by default** in `/settings` to persist this behavior across launches; `/unjail` then unlocks only the current session.
434
435This is a guardrail against accidents, not a hard security boundary. If you need real isolation, run zut under docker or a proper sandbox.
436
437## Sessions
438
439Every interactive or print/json run (unless `--no-session`) writes a JSONL transcript under `$ZUT_HOME/sessions/<cwd-hash>/`. Resume any of them with `--continue`, `--resume`, `--session <path>`, or interactively via `/sessions` inside the TUI. Session metadata stores the provider and model used by that session; resume honors that pair, rebuilding the active agent when it differs and refusing the switch without discarding the current session if rebuilding fails. Empty sessions (the user exited without prompting) are deleted on close so the list stays tidy.
440
441## Providers
442
443zut's built-in provider catalog includes:
444
445- **Subscription-capable**: Anthropic Claude Pro/Max (`anthropic`), OpenAI Codex / ChatGPT Plus/Pro (`openai-codex`), Kimi Code (`kimi`), SuperGrok/X Premium (`xai`), GitHub Copilot (`github-copilot`).
446- **Direct API providers**: Anthropic, OpenAI Chat Completions, OpenAI Responses, DeepSeek, Google Gemini, Kimi/Moonshot, Moonshot CN, Groq, Cerebras, xAI, Together AI, Hugging Face Router, OpenRouter, Mistral, Z.AI, Xiaomi/MiMo token-plan regions, MiniMax global/CN, Fireworks, Vercel AI Gateway, OpenCode/OpenCode Go.
447- **Cloud/platform providers**: Amazon Bedrock, Google Vertex AI, Azure OpenAI, Cloudflare Workers AI, Cloudflare AI Gateway.
448- **Local/compatible**: Ollama, llama.cpp router mode, and OpenAI-compatible local endpoints via `--base-url`.
449
450Use `/login` to store API keys or subscription credentials. `/model` only shows models from providers that are currently available from env vars, `auth.json`, Kimi CLI fallback, local Ollama, or a configured llama.cpp router.
451
452## Models
453
454`--list-models` or the `/model` picker shows the full catalog across all built-in providers. Three sources:
455
456- **Catalog**: models baked into zut, covering Claude, GPT/Codex, Gemini/Gemma, Kimi/Moonshot, DeepSeek, Groq-hosted Llama/Gemma/Compound, OpenRouter-routed models, Bedrock model ids, Vertex model ids, Azure OpenAI deployments, Copilot models, and other provider-specific catalog entries.
457- **Live**: IDs discovered from `GET /v1/models` using your stored API key (cached for 6h in `$ZUT_HOME/models-cache.json`, refreshed in the background on startup).
458- **Speculative**: IDs that appear in the upstream generator but aren't live on the public API yet. They'll 404 today and start working the moment the provider ships them.
459
460The context meter in the status line uses the model's advertised context window to show how much of it your last turn consumed.
461
462### Model fallback (rescue)
463
464When a turn fails because of a recoverable provider error — expired token (`401`), permission denied (`403`), rate limit (`429`), provider outage (`502`/`503`/`504`), or a transient network failure — zut opens a **rescue** picker over the chat instead of just painting a red banner.
465
466The picker is the same vertical list / fuzzy filter UI as `/model`, but it only shows models from providers you're currently logged in to (env vars, `auth.json`, Kimi CLI fallback, ollama). The failed model is excluded. Press `↑`/`↓` to choose, `enter` to retry the **same prompt** on the new model, `esc` to dismiss.
467
468Before the actual provider request fires, the OpenAI / Anthropic / Kimi / DeepSeek / Google / OpenAI-Codex clients also do up to two silent retries with short backoff (250ms, 750ms) on `502`/`503`/`504` and connection-reset / EOF-before-headers errors. Most edge-proxy blips disappear without you ever seeing the rescue picker.
469
470A rescue retry always **drops launch-time `--api-key` and `--base-url`** before rebuilding the agent. Those overrides are usually the reason the rescue triggered (bad key, typo'd base URL, corporate gateway only valid for the originally-picked provider), so the retry re-resolves credentials from env vars / `auth.json` / provider defaults instead. Use `/model` if you want overrides to stick.
471
472No configuration is required — the candidate list is built dynamically from your active credentials. Bad-request / context-length / serialization errors are NOT routed to the rescue picker, because switching models won't fix them; those still surface as a normal error.
473
474### Custom models
475
476Place a `models.json` in `$ZUT_HOME` (`$XDG_STATE_HOME/zut/` when set, otherwise the platform default above) to add models that aren't in the baked-in catalog or to override existing entries:
477
478```json
479{
480  "providers": {
481    "openai": {
482      "models": [
483        {
484          "id": "gpt-5.5",
485          "name": "GPT-5.5",
486          "reasoning": true,
487          "reasoningLevelMap": {"minimum": "low", "max": ""},
488          "contextWindow": 400000,
489          "maxTokens": 128000
490        }
491      ]
492    }
493  }
494}
495```
496
497Supported fields per model: `id` (required), `name`, `reasoning`, `reasoningLevelMap`, `contextWindow`, `maxTokens`, `baseUrl`, `priceInput`, `priceOutput`, `priceCacheRead`, `priceCacheWrite`.
498
499`reasoningLevelMap` is optional. Protocol defaults apply when it is omitted. Add only model-specific exceptions using `minimum`, `low`, `medium`, `high`, `xhigh`, or `max` as keys. Map a key to another level when both inputs are equivalent, or to an empty string or `off` to remove it. The same effective mapping drives `/reasoning` and provider requests.
500
501Provider keys are normalized: `openai-codex` and `openai-responses` map to `openai`, `anthropic-messages` maps to `anthropic`, `moonshot`, `moonshot-ai`, and `kimi-code` map to `kimi`, and `deepseek-chat` and `deepseek-ai` map to `deepseek`. Built-in provider ids such as `groq`, `openrouter`, `github-copilot`, `amazon-bedrock`, `google-vertex`, `azure-openai-responses`, `fireworks`, `vercel-ai-gateway`, `mistral`, and `xai` can also be used directly.
502
503User-defined models show `source: user` in `--list-models` and take precedence over both the baked-in catalog and live-discovered models. Adding a `models.json` does not hide the built-in catalog; entries are merged on top of it. Missing or invalid files are silently ignored.
504
505#### Custom providers
506
507A top-level provider key that is not a built-in id defines a custom provider. Give it a provider-level `baseUrl` and an `api` wire format (`openai` for OpenAI-compatible Chat Completions, the default, `openai-responses` for the OpenAI Responses API, or `anthropic` for the Anthropic Messages API). A model-level `baseUrl` overrides the provider-level one for that model; an unknown `api` value falls back to `openai` with a warning.
508
509```json
510{
511  "providers": {
512    "my-company": {
513      "baseUrl": "https://llm.mycompany.com/v1",
514      "api": "openai",
515      "models": [
516        { "id": "company-llm-v2", "name": "Company LLM v2" }
517      ]
518    }
519  }
520}
521```
522
523Custom providers are first-class: they appear in `--list-models`, `/model`, and `/login`. `models.json` never stores secrets. Supply the key through `/login`, `--api-key`, or a derived environment variable in upper snake case (so `my-company` reads `MY_COMPANY_API_KEY`). Because many self-hosted gateways do not expose a model-list endpoint, custom provider keys are accepted and stored without a verification probe; an invalid key surfaces on the first model call.
524
525To retrieve this custom provider's key from a password manager, add a matching entry to `$ZUT_HOME/auth.json`:
526
527```json
528{
529  "additional_api_key_creds": {
530    "my-company": {
531      "api_key_command": {
532        "program": "op",
533        "args": ["read", "op://Work/OpenAI/credential"],
534        "timeout_ms": 120000
535      }
536    }
537  }
538}
539```
540
541The provider IDs in `models.json` and `auth.json` must match. Then select the custom model directly:
542
543```bash
544zut --provider my-company --model company-llm-v2
545```
546
547### Kimi Code
548
549zut has built-in Kimi support through the Kimi Coding endpoint and Moonshot's OpenAI-compatible chat API.
550
551```bash
552zut --provider kimi
553```
554
555By default this uses:
556
557- model: `kimi-for-coding`
558- base URL: `https://api.kimi.com/coding/v1`
559
560Credential lookup order for Kimi:
561
5621. `--api-key`
5632. `KIMI_API_KEY`
5643. `MOONSHOT_API_KEY`
5654. `$ZUT_HOME/auth.json`
5665. the official Kimi Code CLI token at `~/.kimi/credentials/kimi-code.json`, unless disabled by `/logout kimi`
567
568Use `/login` for either API-key login or Kimi Code subscription login. The subscription flow uses Kimi Code's device-code OAuth flow: zut opens the verification URL, waits for browser approval, stores the token in `auth.json`, and refreshes it automatically.
569
570For direct Moonshot API keys or a custom compatible endpoint:
571
572```bash
573zut --provider kimi --model kimi-k2-0905-preview --base-url https://api.moonshot.ai/v1 --api-key "$KIMI_API_KEY"
574```
575
576Kimi K3 is built in as `kimi/k3`, `moonshotai/kimi-k3`, `moonshotai-cn/kimi-k3`, `opencode-go/kimi-k3`, `openrouter/moonshotai/kimi-k3`, and `vercel-ai-gateway/moonshotai/kimi-k3`. Its output limit is 131,072 tokens on every built-in route.
577
578You can add additional Kimi/Moonshot model IDs to `models.json` under the `kimi` provider.
579
580### xAI
581
582xAI supports either `XAI_API_KEY` or `/login` subscription authentication. The subscription option is labeled `Sign in with SuperGrok or X Premium`, opens a prefilled device-authorization URL, and refreshes the stored token automatically. The default xAI model is `grok-4.5`, sent through the Responses API.
583
584### DeepSeek
585
586zut has built-in DeepSeek support through DeepSeek's OpenAI-compatible chat API.
587
588```bash
589zut --provider deepseek
590```
591
592By default this uses:
593
594- model: `deepseek-v4-pro`
595- base URL: `https://api.deepseek.com/v1`
596
597Catalog ships with `deepseek-v4-pro` (reasoning) and `deepseek-v4-flash`. These are exactly the IDs returned by `GET https://api.deepseek.com/models` today. You can add additional model IDs to `models.json` under the `deepseek` provider.
598
599Credential lookup order for DeepSeek:
600
6011. `--api-key`
6022. `DEEPSEEK_API_KEY`
6033. `$ZUT_HOME/auth.json`
604
605Use `/login` and pick **api key** to paste a DeepSeek key. zut probes `/v1/models` once and stores the key under `deepseek` in `auth.json`.
606
607> **Auth model: API key only.** DeepSeek does not offer a subscription OAuth flow. The `/login subscription` step lists only Anthropic, OpenAI, and Kimi; DeepSeek shows up only under `/login → api key`.
608
609> **Text only at the wire level.** DeepSeek's chat-completions endpoint currently rejects the multimodal content schema (`unknown variant image_url, expected text`). When the active provider is `deepseek`, zut silently drops `ImageBlock` parts from outgoing user/tool messages and keeps only the text. Switching back to a vision-capable model (Claude, GPT-4o/5, Gemini) re-sends the image normally because the session file still stores it.
610
611For a custom-compatible endpoint (mirror, gateway, self-host):
612
613```bash
614zut --provider deepseek --base-url https://my-deepseek-mirror.example.com/v1 --api-key "$DEEPSEEK_API_KEY"
615```
616
617### Google Gemini
618
619zut has built-in Google Gemini support through the [AI Studio Generative Language API](https://aistudio.google.com/).
620
621```bash
622zut --provider google
623```
624
625By default this uses:
626
627- model: `gemini-2.5-pro`
628- base URL: `https://generativelanguage.googleapis.com`
629
630Catalog ships with `gemini-2.5-pro`, `gemini-2.5-flash`, `gemini-2.5-flash-lite`, `gemini-2.0-flash`, and `gemini-2.0-flash-lite`. Live discovery against `/v1beta/models` adds anything else your key can see.
631
632Credential lookup order for Google:
633
6341. `--api-key`
6352. `GEMINI_API_KEY`
6363. `GOOGLE_API_KEY`
6374. `$ZUT_HOME/auth.json`
638
639Use `/login` and pick **api key** to paste an AI Studio key. zut probes `/v1beta/models` once and stores the key under `google` in `auth.json`.
640
641> **Auth model: API key only (this provider).** Google does not issue OAuth tokens for consumer Gemini Advanced / Google One AI Premium subscriptions, so there is no "log in with your Google subscription" flow. The `/login subscription` step quietly downgrades to the api-key form when you pick Google so you don't end up in a dead end. If you need OAuth/service-account auth instead of an API key, use the `google-vertex` provider below.
642
643> **Free-tier rate limits.** AI Studio's free tier has tight per-minute and per-day caps that vary by model: `gemini-2.5-pro` is the strictest (a few requests per minute, ~50 per day), Flash and Flash-Lite are far more generous. If a Pro turn 429s with `"You exceeded your current quota"` while Flash on the same key still works, you've hit the Pro free-tier RPD. Either switch to Flash for agent loops, or [enable billing](https://aistudio.google.com/app/apikey) on your AI Studio project to flip the same key from free to pay-as-you-go pricing (`$1.25/M` input, `$10/M` output for Pro).
644
645Reasoning levels (`--reasoning off|minimum|low|medium|high|xhigh|max`, also configurable through `/reasoning` or in `/settings` as **reasoning level**) map differently per generation. `max` is a distinct opt-in tier above `xhigh`. GPT-5.6 and adaptive-thinking Claude models receive native `max`; unsupported providers clamp it to their highest accepted effort. Budget-based providers retain their provider/model caps. Gemini 3.x uses the `thinkingLevel` enum (`MINIMAL`/`LOW`/`MEDIUM`/`HIGH`), with Gemini-3-Pro pinned to `LOW` minimum and `HIGH` for any medium-or-higher request. `off` sends no reasoning config. Gemini 2.0 models have no thinking config.
646
647You can add additional Gemini model IDs to `models.json` under the `google` provider.
648
649### Gemini Enterprise Agent Platform (formerly Google Vertex AI)
650
651zut also has built-in support for [Gemini Enterprise Agent Platform](https://cloud.google.com/products/gemini-enterprise-agent-platform), Google's enterprise/GCP-hosted Gemini endpoint. Unlike the AI Studio `google` provider above, the `google-vertex` provider supports a Google Cloud API key plus `service_account` and `authorized_user` credential files. It does not support consumer Google login or the complete ADC credential chain, such as metadata-server and workload-identity credentials.
652
653```bash
654zut --provider google-vertex
655```
656
657Required configuration (env vars, read at construction time):
658
659- `GOOGLE_CLOUD_PROJECT` — required, your GCP project id.
660- `GOOGLE_CLOUD_LOCATION` — optional, defaults to `us-central1`.
661
662Credential lookup order for Vertex:
663
6641. `GOOGLE_CLOUD_API_KEY`: simplest option. An API key created in the GCP console is sent as `x-goog-api-key`, without a token exchange.
6652. `GOOGLE_APPLICATION_CREDENTIALS`: path to a supported credential JSON file.
6663. **Default ADC file**: if neither of the above is set, zut checks the file written by `gcloud auth application-default login`. This is `~/.config/gcloud/application_default_credentials.json` on Unix systems and `%APPDATA%\gcloud\application_default_credentials.json` on Windows.
667
668Two credential file shapes are supported:
669
670- `type: "service_account"`: zut signs a JWT with the private key and exchanges it for a short-lived access token.
671- `type: "authorized_user"`: zut exchanges the stored client ID, client secret, and refresh token for a short-lived access token.
672
673Access tokens are cached in memory and refreshed on demand.
674
675If none of these are available, zut errors with `vertex: no auth — set GOOGLE_CLOUD_API_KEY or GOOGLE_APPLICATION_CREDENTIALS`.
676
677### Local models with ollama
678
679zut works with [ollama](https://ollama.com) out of the box. Ollama serves an OpenAI-compatible API locally, so any model you have pulled works with zut.
680
681Quick start:
682
683```bash
684ollama pull qwen3.5:4b
685zut --provider ollama --model qwen3.5:4b
686```
687
688That's it. No API key needed for local models. zut defaults to `http://localhost:11434`.
689
690For a remote ollama instance or one behind auth:
691
692```bash
693zut --provider ollama --model llama3 --base-url https://my-server.com/v1 --api-key my-token
694```
695
696You can also add models to your `models.json` so you don't need flags every time:
697
698```json
699{
700  "providers": {
701    "ollama": {
702      "models": [
703        {
704          "id": "qwen3.5:4b",
705          "name": "Qwen 3.5 4B",
706          "contextWindow": 32768,
707          "maxTokens": 8192
708        }
709      ]
710    }
711  }
712}
713```
714
715The `ollama` provider uses the OpenAI chat completions protocol internally, so it also works with any OpenAI-compatible server (vLLM, LM Studio, LocalAI, etc.).
716
717### Local models with llama.cpp router mode
718
719zut can connect to a recent [llama.cpp](https://github.com/ggml-org/llama.cpp) router, manage its GGUF files, and use loaded models through the router's OpenAI-compatible inference API. This is separate from Ollama. An Ollama server normally listens on port `11434` and should use zut's `ollama` provider instead.
720
721Install or update llama.cpp. On macOS with Homebrew:
722
723```bash
724brew install llama.cpp
725# or, when already installed
726brew upgrade llama.cpp
727```
728
729Create a directory for GGUF files and start `llama-server` without `--model`, `-m`, or `-hf`. Supplying one of those options starts a single model rather than the router API zut needs.
730
731```bash
732mkdir -p ~/llama-models
733
734llama-server \
735  --models-dir ~/llama-models \
736  --no-models-autoload \
737  --jinja \
738  --host 127.0.0.1 \
739  --port 8080 \
740  -ngl 999 \
741  -c 32768
742```
743
744`--no-models-autoload` leaves load decisions to `/llama`. `--jinja` enables model chat templates and improves tool-call compatibility. `-ngl 999` requests maximum GPU offload, while `-c 32768` limits each loaded model to a 32K context. Adjust these values for your hardware.
745
746Confirm that router mode is active before configuring zut:
747
748```bash
749curl http://127.0.0.1:8080/health
750curl http://127.0.0.1:8080/models
751```
752
753The models request must return JSON with a `data` array. A 404 usually means the server is outdated, running on a different port, or was started in single-model mode.
754
755In zut, run `/login`, choose **api key**, and select **llama.cpp**. Enter `http://127.0.0.1:8080` as the router URL and leave the API key empty for a local-only server. Do not enter `/v1`; zut derives the inference URL itself. The saved URL and optional key live in `$ZUT_HOME/auth.json`.
756
757You can configure the same connection through environment variables:
758
759```bash
760export LLAMA_BASE_URL=http://127.0.0.1:8080
761export LLAMA_API_KEY=optional-secret
762```
763
764When using a key, launch the server with the matching `--api-key` value. Keep `--host 127.0.0.1` unless remote clients must reach the router.
765
766Run `/llama` to:
767
768- inspect the router's current model states
769- search Hugging Face for GGUF repositories
770- choose a quantization and download it with byte progress
771- explicitly load or unload a model
772- press `d` to ask the router to remove a downloaded cache model after confirmation
773
774Models discovered through `--models-dir` or a preset cannot be removed by zut. Delete those files from their configured source instead. The router removes the selected GGUF from its Hugging Face cache, but some llama.cpp versions retain shared repository artifacts such as `mmproj` files. Remove the repository's cache directory manually if those artifacts are no longer needed. Hugging Face search uses `HF_TOKEN` when available. Gated repositories require prior access approval, and the `llama-server` process also needs an authorized `HF_TOKEN` because the server performs the download.
775
776Opening `/model` refreshes the router and lists every loaded model under provider `llama.cpp`. Unloaded models are intentionally omitted because they cannot answer inference requests. Load them through `/llama` first, then select them through `/model`.
777
778A model installed through Ollama is kept in Ollama's internal storage and is not automatically available as a llama.cpp GGUF file. Download a GGUF copy through `/llama` or place GGUF files in `~/llama-models`, then restart the router so it discovers files added manually.
779
780## Clipboard images
781
782In the main chat, `ctrl+v` checks the system clipboard for an image before falling back to text. A pasted image appears as a `[clipboard image #N]` marker and is attached when you submit the prompt; `esc` or `ctrl+c` clears pending image markers with the rest of the input. Wayland image paste uses `wl-paste` from `wl-clipboard`; X11 image paste uses `xclip` when available. Clipboard images larger than 32 MiB are ignored and use the normal text-paste fallback.
783
784## Inline images
785
786When a tool returns an image (for example `read` on a PNG), zut renders it inline on terminals that support it: **Ghostty**, **Kitty**, **iTerm2**, **WezTerm**. On other terminals you see a text placeholder with MIME type, pixel dimensions, and byte size. Control with the `ZUT_INLINE_IMAGES` env var:
787
788| Value | Effect |
789|---|---|
790| unset (default) | Auto-detect based on `TERM_PROGRAM`; use the text placeholder inside VS Code and Herdr. |
791| `iterm`, `iterm2` | Force the iTerm2 OSC 1337 protocol. |
792| `kitty` | Force the Kitty graphics protocol. |
793| `off`, `none` | Always use the text placeholder. |
794
795Herdr's Kitty graphics support is currently experimental, so zut does not enable inline images there automatically. After enabling `experimental.kitty_graphics` in Herdr, set `ZUT_INLINE_IMAGES=kitty` to opt in.
796
797Frames containing images are full-repainted (no differential diff) to prevent stale image pixels from lingering through scroll. That costs one terminal flash per image-containing frame; set `ZUT_INLINE_IMAGES=off` if that bothers you.
798
799## Tool rendering
800
801By default each tool call (bash, read, write, edit, create_worktree, lsp) renders inside a bordered panel — a `┌─ header ─┐`, `│`-prefixed body rows, and a `└─┘` footer. On a screen with many calls the borders can read as busy, so zut also offers a **flat** mode: a single quiet header line per call (`▌ bash …`) with indented, border-free output. Same information — tool name, arg summary, streamed output, the `... (N more lines, ctrl+o to expand)` truncation — just no frame.
802
803Set the `tool_render` key in `$ZUT_HOME/config.json`:
804
805```json
806{
807  "tool_render": "flat"
808}
809```
810
811| Value | Effect |
812|---|---|
813| unset / `"box"` (default) | Each tool call is wrapped in a bordered panel. |
814| `"flat"` | Boxless: a quiet header line plus indented output. |
815
816The `ZUT_FLAT_TOOLS` env var overrides the config for a single run, which is handy for trying it without editing the file:
817
818| Value | Effect |
819|---|---|
820| `1`, `true`, `yes`, `on`, `flat` | Force flat rendering. |
821| `0`, `false`, `no`, `off`, `box` | Force the bordered panel. |
822| unset | Fall back to the `tool_render` config key. |
823
824```sh
825ZUT_FLAT_TOOLS=1 zut   # flat, just this run
826ZUT_FLAT_TOOLS=0 zut   # boxes, even if config.json says "flat"
827```
828
829Either way, theme colors still drive the rendering (the header uses your accent/foreground, output uses the tool-output color) and `ctrl+o` still expands a truncated result.
830
831### Tool arg width
832
833The header line for a tool call shows the tool name plus a one-line summary of its primary argument — a `path`, a `command`, or a query. That summary is truncated to 60 cells by default (`web_answer What is the best architecture to implement resilience wit...`). On a wide terminal that can clip long queries more than you'd like, so set the `ZUT_TOOL_ARG_WIDTH` env var to raise (or lower) the limit:
834
835```sh
836ZUT_TOOL_ARG_WIDTH=120 zut   # allow up to 120 cells before truncating
837```
838
839| Value | Effect |
840|---|---|
841| unset (default) | Truncate the arg summary at 60 cells. |
842| integer in `[20, 500]` | Truncate at that many cells instead. |
843| anything else | Ignored; falls back to the 60-cell default. |
844
845## Compact input
846
847By default a message you send renders as a padded, background-tinted bubble: a blank tinted row above and below the text, with a `▌` accent bar down the left. So even a one-line prompt occupies three rows. Set `compact_input` to collapse it to a single quiet `▌ your text` gutter line per wrapped row — no padding rows, no background tint.
848
849```json
850{
851  "compact_input": true
852}
853```
854
855| Value | Effect |
856|---|---|
857| unset / `false` (default) | Padded, background-tinted user bubble. |
858| `true` | One quiet gutter line per wrapped row. |
859
860The `ZUT_COMPACT_INPUT` env var overrides the config for a single run (`1`/`true`/`on`/`compact` force compact; `0`/`false`/`off`/`bubble` force the bubble):
861
862```sh
863ZUT_COMPACT_INPUT=1 zut   # compact, just this run
864```
865
866## Queued messages
867
868You can keep typing while the agent is working. Pressing `enter` during a turn queues the message instead of interrupting: it shows up above the status bar as `sliding in: <text>` and is delivered as the next user turn the moment the current one finishes. Queue as many as you want; they run in order. `esc` cancels the active turn and drops the queue so a runaway turn doesn't flood you with stale follow-ups; `ctrl+c` while busy arms the exit hint instead of interrupting, a second `ctrl+c` within two seconds exits zut.
869
870To recover the most recently queued message back into the editor (to tweak it before it runs), press `Option+↑`. In VS Code's integrated terminal that chord doesn't survive xterm.js's macOS key handling — use `Option+Shift+↑` there. zut's hint line under the sliding-in queue adapts automatically based on `$TERM_PROGRAM`.
871
872Slash commands also work while the agent is busy. Non-destructive ones (`/help`, `/jump`, `/btw`, `/sessions`, `/skills`, `/reasoning`, `/settings`, `/jail`, `/unjail`, `/exit`) take effect immediately. Destructive ones (`/clear`, `/compact`, `/login`, `/logout`, `/model`, `/reload-ext`) cancel the active turn first and then run.
873
874
875## Keys (interactive mode)
876
877### Input
878
879| Key | Action |
880|---|---|
881| `enter` | Submit (queued if the agent is busy). |
882| `alt+enter` | Newline. |
883| `tab` | Complete the selected slash command. |
884| `esc` | Cancel the current turn (while busy); clear input (while idle). Two parsed bare `Esc` presses within 500 ms open `/session tree` only when the editor is idle and empty; dialogs, busy/queued work, and modified keys keep their existing precedence. |
885| `ctrl+c` | Clear the input and queue (while idle) or arm the exit hint (while busy). Press again within 2s to exit. Use `esc` to cancel a running turn. |
886| `ctrl+d` | Exit on empty input. |
887| `ctrl+b` | Toggle the right sidebar; hidden or narrow widgets use a bounded above-input fallback. |
888| `ctrl+l` | Redraw the screen. |
889| `ctrl+v` | Paste clipboard text into the focused chat, side chat, dialog, filter, or credential input. In the main chat, image clipboard content is attached to the next prompt when the platform exposes it (macOS pasteboard, Wayland `wl-paste`, or X11 `xclip`). On Linux, text uses `wl-paste`, `xclip`, or `xsel`; terminal-native bracketed paste remains available without those commands. |
890| `ctrl+o` | Expand or collapse long tool results (read, write, edit, bash, create_worktree, lsp, and web_search outputs over ~12 lines). |
891| `ctrl+1` ... `ctrl+9` | Switch to the model bound to that quick-model slot (configured in `/settings` -> model shortcuts). No-op while a turn is running. |
892| `@` | Open the file picker. Browse files and directories in the working directory. |
893
894### File picker (`@`)
895
896| Key | Action |
897|---|---|
898| `@` | Open the file picker (type after a space or at the start of input). |
899| `up`, `down` | Navigate the file list. |
900| `right` | Open the selected directory. |
901| `left` | Go back to the parent directory. |
902| `enter` | Select the file or directory and insert it as a chip (`[file:name]` or `[dir:name/]`). |
903| `esc` | Close the file picker. |
904
905Type `@` followed by a filter string to narrow the list (e.g. `@read` shows only entries containing "read"). Selected files are inserted as compact chips that expand to the full path on submit. Dragged-and-dropped files and directories also collapse to chips automatically.
906
907### Editor line navigation
908
909| Key | Action |
910|---|---|
911| `ctrl+a`, `ctrl+e` | Jump to start or end of line. |
912| `alt+left`, `alt+right` | Jump one word back or forward. |
913| `ctrl+u`, `ctrl+k` | Delete to start or end of line. |
914| `ctrl+w`, `alt+backspace` | Delete the previous word. |
915| `up`, `down` | Move within multi-line input. At the top edge, `up` recalls previous prompts and `down` moves forward through prompt history. |
916
917### Chat scroll
918
919| Key | Action |
920|---|---|
921| `pgup`, `pgdn` | Scroll one page up or down. |
922| `up`, `down` (editor empty, not browsing prompt history) | Scroll three lines up or down. This is how the mouse wheel reaches the scroll logic on most terminals. |
923
924## Extensions
925
926zut can be extended in any language via a subprocess + JSON-RPC protocol. Extensions can register slash commands, expose tools to the model, intercept tool calls (block or rewrite args), gate whole turns before the model is called, and rewrite the assistant's visible text before it reaches the user. None are installed by default; opt in explicitly. Hot-reload any time with `/reload-ext`.
927
928### Install and manage
929
930```bash
931zut ext install <path|git-url>   # copy / clone into $ZUT_HOME/extensions/
932zut ext install --build=go <path> # explicitly build and install local Go source
933zut ext list                      # show installed extensions
934zut ext doctor                    # diagnose load, registration, and conflict issues
935zut ext logs <name> [-f]          # cat or tail the extension's stderr log
936zut ext enable <name>             # re-enable a disabled extension
937zut ext disable <name>            # disable without removing
938zut ext remove <name>             # delete an extension directory
939```
940
941For local installs, zut validates `extension.json` and any executable path
942relative to the extension directory before reporting success. It never runs a
943build implicitly. Use `zut ext install --build=go <path>` to explicitly build a
944local Go extension; other source-based extensions must provide their runtime
945artifact or launcher themselves. A failed validation or build leaves no
946partial installation behind.
947
948`zut ext doctor` keeps normal extension startup fail-soft, but gives
949you an explicit troubleshooting view: manifest errors, disabled or
950shadowed extensions, subprocess load errors, ready/auto-ready status,
951registered commands/tools, registration conflicts, warnings, and the
952stderr log path.
953
954For development, point `zut --ext <path>` at a working directory and skip the install step entirely. Repeatable; takes precedence over installed extensions of the same name.
955
956### Updating extensions
957
958`zut update` refreshes the zut binary **and** every installed extension that lives in a git checkout. Per-extension behaviour:
959
960- Disabled extensions are skipped.
961- Extensions without a `.git/` directory (installed by `zut ext install ./local-path`) are skipped — there is no remote to pull from.
962- For the rest, zut stashes any dirty worktree state (including untracked runtime files like `todos.json` or `config.json`), runs `git pull --ff-only`, and pops the stash. If the pop produces conflicts, the conflict markers are left in place and you'll see a warning.
963- Diverged branches, offline pulls, or any other git failure are reported as `failed` and the next extension is processed. `zut update` itself never aborts because of an extension.
964- zut does **not** run any build step (`go build`, `npm install`, `make`) after the pull. Extension authors are expected to commit the runnable artifact (binary, transpiled JS, etc.). If you need a build, run it explicitly, reinstall the extension, or use `/reload-ext` for a working-tree copy.
965
966### Theme-only extensions
967
968An extension may ship only a theme: `extension.json` plus `theme.json` (or `themes/theme.json`) and no executable. zut loads it without spawning a subprocess and shows it in `/settings` with source information. See [docs/themes.md](docs/themes.md).
969
970### Reference
971
972`examples/extensions/` ships reference implementations in Go, TypeScript, Node, and shell, including `tasked-phases` for spec-driven phase/checklist tracking. See [docs/extensions.md](docs/extensions.md) for the full protocol, the SDK API (`packages/agent/ext`), and the phase roadmap.
973
974## Skills
975
976A skill is a per-folder `SKILL.md` file with a YAML frontmatter header. zut discovers skills at startup, surfaces their names in the system prompt, and exposes a built-in `skill` tool the model uses to load the body on demand.
977
978By default zut loads built-in skills plus user-installed skills from:
979
980- `./.zut/skills/<name>/SKILL.md` (project)
981- `$ZUT_HOME/skills/<name>/SKILL.md` (global)
982- `./.claude/skills/<name>/SKILL.md`, `~/.claude/skills/<name>/SKILL.md` (Claude-compatible layout)
983- `./.agents/skills/<name>/SKILL.md`, `~/.agents/skills/<name>/SKILL.md` (agent-compatible layout)
984
985User skill roots are scanned recursively. A nested skill keeps its frontmatter `name` and can also be loaded by its slash-separated path relative to the skill root, such as `systems-backend/subskills/golang-patterns`.
986
987See [docs/skills.md](docs/skills.md) for the frontmatter fields, authoring tips, and example skills under `examples/skills/`.
988
989## Telegram bot (bridge)
990
991zut can run as a telegram bot so you can DM it from your phone. Two ways to run it: **from inside the TUI** (the running session mirrors into Telegram) or **as a standalone background daemon** (a headless bot with its own independent agent).
992
993### From inside the TUI
994
995Type `/telegram` in the running TUI to open a picker with **connect**, **disconnect**, and **status**. When connected:
996
997- DMs from the paired user become prompts in the **same** session you're typing in, so you can continue a conversation from the terminal on your phone and back again.
998- Messages you type in the TUI are mirrored into the Telegram thread prefixed `you: ...` and the assistant's replies come back prefixed `zut: ...`, so the Telegram chat stays a complete record of both sides of the conversation.
999- Messages sent from Telegram show up as your own bubble in Telegram (no mirror) and the assistant's reply to them comes back bare (no prefix).
1000- The status bar shows a `- tg -` tag while the bridge is active.
1001- `/telegram connect` / `/telegram disconnect` / `/telegram status` (or `/tg`) also work as direct commands without the picker.
1002
1003The in-TUI bridge refuses to start while the standalone daemon (below) is running, since two concurrent long-poll consumers of the same bot race on every update and silently drop messages.
1004
1005### Standalone daemon
1006
1007For headless servers or long-running bots unattached to a TUI:
1008
1009```bash
1010zut telegram-bot setup     # paste a BotFather token, verify, save
1011zut telegram-bot run       # foreground: long-poll in this terminal (ctrl+c to stop)
1012zut telegram-bot start     # background: detach and return immediately
1013zut telegram-bot stop      # SIGTERM the background bot (SIGKILL after 5s)
1014zut telegram-bot logs -f   # tail $ZUT_HOME/logs/bot.log (omit -f to just cat)
1015zut telegram-bot status    # config (token masked) + running/stopped
1016zut telegram-bot reset     # forget the token and paired user
1017# short alias: `zut tg ...` is accepted for every subcommand
1018```
1019
1020The background flavor writes the child's PID to `$ZUT_HOME/bot.pid` and redirects stdout and stderr to `$ZUT_HOME/logs/bot.log`. `zut telegram-bot stop` reads that PID, sends SIGTERM, waits up to five seconds, then escalates to SIGKILL if the child is still alive. Running two instances at once is refused at startup.
1021
1022> **Use the installed binary for `start`.** `go run ./cmd/zut telegram-bot start` won't work. `go run` builds a binary in a temp directory and deletes it when it exits, which kills the detached child. Run `make install` (or `go build`) first and invoke the installed binary.
1023
1024Setup flow:
1025
10261. Talk to [@BotFather](https://t.me/BotFather) on telegram, run `/newbot`, copy the token it gives you.
10272. Run `zut telegram-bot setup` and paste the token when prompted.
10283. Run `zut telegram-bot run` in the directory you want the agent to operate in.
10294. Open your bot on telegram, send `/start`. The first user to do this claims the bridge (stored as `allowed_user_id`); every other user is rejected.
1030
1031From then on, any DM you send is forwarded to the agent as a user prompt. Attached photos or `image/*` documents are downloaded and passed to vision-capable models. In-bot telegram commands are case-insensitive: `/help`, `/status`, `/stop` (cancel the current turn). Config lives in `$ZUT_HOME/bot.json` (mode 0600).
1032
1033Starting either Telegram bridge removes any webhook configured for that bot before long polling begins, while preserving pending updates. Telegram does not allow webhooks and `getUpdates` polling at the same time, so do not share the bot token with another service that expects to keep a webhook active.
1034
1035Bot mode respects the usual zut flags: `--provider`, `--model`, `--cwd`, `--reasoning`, `--continue`, `--no-session`, `--no-tools`, and so on. Run `zut tg run -c --model claude-opus-4-1` to resume the latest session on Opus, for example.
1036
1037### Architecture: protocol-agnostic bot core
1038
1039The messenger functionality is split in two layers. A generic, protocol-agnostic core lives in `packages/agent/modes/bot`: it owns the turn queue, agent prompting, built-in command dispatch (`/start`, `/help`, `/status`, `/stop`), status formatting, and per-turn credential refresh. Concrete transports implement the small `BotAdapter` interface (inbound polling, sending replies, a typing indicator, and optional protocol-specific status text); the Telegram support in `packages/agent/modes/telegram` is one such adapter.
1040
1041This means additional messaging backends (Discord, Slack, Signal, and similar) can be added by implementing `BotAdapter` in a new package and wiring up a subcommand. No changes to the runner, agent, or core are required. Channel IDs are opaque strings owned by the adapter, so the shared runner stays free of protocol-specific types.
1042
1043## Development
1044
1045```bash
1046make help      # list the important developer commands
1047make build     # build ./bin/zut as 0.0.0-dev
1048make test      # go test -race ./...
1049make test-fast # go test ./...
1050make lint      # golangci-lint + go vet + gofmt check
1051make lint-install # install the pinned golangci-lint version
1052make fmt       # gofmt -w .
1053make install   # install the current checkout with go install
1054make go-install # install the latest published module version
1055make release VERSION=0.1.0 # cross-compile release binaries
1056```
1057
1058Source layout (single Go module, four packages under `packages/`):
1059
1060```
1061cmd/zut/                              main()
1062packages/provider/                    LLM client surface, model catalog, streaming clients
1063packages/provider/auth/               credential store, api-key probe, oauth, login server
1064packages/core/                        agent loop, sessions, cost tracking, compaction
1065packages/tui/                         terminal raw-mode, input parser, editor, renderer, markdown, view
1066packages/agent/                       cli wiring, arg parsing, system prompt, config
1067packages/agent/lsp/                    LSP clients, server discovery, linters, diagnostics
1068packages/agent/extensions/            extension subprocess manager
1069packages/agent/extproto/              extension wire-format types
1070packages/agent/modes/                 interactive tui, print, json, dialogs
1071packages/agent/modes/bot/             protocol-agnostic bot runner (BotAdapter interface)
1072packages/agent/modes/telegram/        telegram adapter, api client, daemon
1073packages/agent/tools/                 read, write, edit, bash, create_worktree, lsp, web search, sandbox
1074packages/agent/skills/                skill discovery, frontmatter parser, skill tool
1075packages/agent/subagents/             named profiles, supervisor, and background runtime
1076packages/agent/sdk/                   public Go SDK for embedding zut in-process (package sdk)
1077packages/agent/ext/                   public Go SDK for writing extensions (package ext)
1078```
1079
1080Downstream consumers can depend on individual packages:
1081`go get github.com/bnema/zut/packages/core` pulls only `core` and its transitive deps (today: `provider`), no agent or TUI code.
1082
1083## License
1084
1085MIT

README.md RawHistoryFolder

zut

What is it?

Install

One-liner (macOS, Linux)

One-liner (Windows, PowerShell)

go install

From source

Prebuilt binaries

Authenticate

Credential lookup order

API keys from commands

/login flow

Token refresh

Persistent instructions (AGENTS.md)

Changelog on update

Usage

Flags

Tools

Modes

zutfile agents

Embedding

Slash commands

Shell escape (!command)

/sessions

/session

/jump

/btw

/subagents

Named subagent profiles

/settings

/skills

/compact

/jail

Sessions

Providers

Models

Model fallback (rescue)

Custom models

Custom providers

Kimi Code

xAI

DeepSeek

Google Gemini

Gemini Enterprise Agent Platform (formerly Google Vertex AI)

Local models with ollama

Local models with llama.cpp router mode

Clipboard images

Inline images

Tool rendering

Tool arg width

Compact input

Queued messages

Keys (interactive mode)

Input

File picker (@)

Editor line navigation

Chat scroll

Extensions

Install and manage

Updating extensions

Theme-only extensions

Reference

Skills

Telegram bot (bridge)

From inside the TUI

Standalone daemon

Architecture: protocol-agnostic bot core

Development

License

README.md Raw History Folder

`/login` flow

Shell escape (`!command`)

`/sessions`

`/session`

`/jump`

`/btw`

`/subagents`

`/settings`

`/skills`

`/compact`

`/jail`

File picker (`@`)