1package agent
2
3import (
4 "bufio"
5 "context"
6 "encoding/json"
7 "errors"
8 "fmt"
9 "io"
10 "os"
11 "strings"
12 "sync"
13 "time"
14
15 "github.com/bnema/zut/packages/agent/extensions"
16 "github.com/bnema/zut/packages/agent/extproto"
17 "github.com/bnema/zut/packages/agent/modes"
18 "github.com/bnema/zut/packages/agent/tools"
19 "github.com/bnema/zut/packages/core"
20 "github.com/bnema/zut/packages/provider"
21)
22
23// runRPCMode implements the JSON-over-stdin/stdout RPC protocol.
24//
25// Wire format: one JSON object per line in both directions.
26//
27// Commands (stdin):
28//
29// {"id":"1","type":"prompt","message":"hello","images":[]}
30// {"id":"2","type":"abort"}
31// {"id":"3","type":"compact"}
32// {"id":"4","type":"get_state"}
33// {"id":"5","type":"set_model","model":"claude-opus-4-5"}
34// {"id":"6","type":"set_reasoning","reasoning":"max"}
35// {"id":"6","type":"get_messages"}
36// {"id":"7","type":"clear"}
37// {"id":"8","type":"get_models"}
38//
39// Responses (stdout): {"type":"response","id":"1","command":"prompt","success":true}
40// Events (stdout): one JSON object per AgentEvent (same schema as --json mode).
41// Extensions may additionally emit ext_status with extension/key/level/text,
42// ext_widget with extension/id/position/title/lines, and ext_widget_clear
43// with extension/id when loaded extensions publish persistent UI state.
44//
45// Auth: if $ZUTCORE_RPC_TOKEN is set, the first command must be
46// {"type":"hello","token":"..."} or the connection is closed.
47func runRPCMode(ctx context.Context, args Args, version string) error {
48 if args.NoYolo {
49 fmt.Fprintln(os.Stderr, "warning: --no-yolo has no effect in rpc mode (no interactive prompt available); tools will run without confirmation")
50 }
51 r, err := Resolve(args, true)
52 if err != nil {
53 return err
54 }
55
56 // Construct the RPC event sink before extension startup. Alerts can
57 // arrive as soon as an extension is ready; rpcServer queues them until
58 // the command loop has started and, when configured, authenticated.
59 server := &rpcServer{
60 ctx: ctx,
61 args: args,
62 provider: r.Provider,
63 model: r.Model,
64 out: os.Stdout,
65 version: version,
66 }
67
68 // Extensions: same lifecycle as interactive mode, minus the
69 // host-hooks integration. Notify/Display calls from extensions
70 // emit RPC events instead of TUI lines so any consumer can react.
71 extHooks := &rpcExtHooks{server: server}
72 extMgr := extensions.New(ZutHome(), r.CWD, version, r.Provider, r.Model, extHooks)
73 for _, e := range extMgr.LoadExplicit(ctx, args.Exts) {
74 fmt.Fprintln(os.Stderr, "extension load:", e)
75 }
76 if !args.NoExt {
77 for _, e := range extMgr.Discover(ctx) {
78 fmt.Fprintln(os.Stderr, "extension load:", e)
79 }
80 }
81 extMgr.WaitForReady(3 * time.Second)
82 defer extMgr.Stop(2 * time.Second)
83 r.MergeExtensionTools(&extToolAdapter{mgr: extMgr})
84
85 ag := r.NewAgent()
86 defer closeAgentLSP(ag)
87 server.agent = ag
88 ag.BeforeToolExecute = func(call provider.ToolCallBlock) (bool, string, json.RawMessage) {
89 r := extMgr.InterceptToolCall(ctx, call.ID, call.Name, call.Arguments)
90 if r.Block {
91 return false, r.Reason, nil
92 }
93 return true, "", r.ModifiedArgs
94 }
95 ag.BeforeTurnContext = func(turnCtx context.Context, step int) (bool, string, string) {
96 r := extMgr.InterceptTurnStart(turnCtx, step)
97 return !r.Block, r.Reason, r.Context
98 }
99 ag.BeforeAssistantMessage = func(text string) (bool, string, string) {
100 r := extMgr.InterceptAssistantMessage(ctx, text)
101 if r.Block {
102 return false, r.Reason, ""
103 }
104 return true, "", r.ReplaceText
105 }
106 ag.OnEvent = func(ev core.AgentEvent) { fanoutAgentEvent(extMgr, ev) }
107
108 // /reload-ext hot-reload callback (also triggered via rpc
109 // `reload_ext` if/when added). Rebuilds the tool registry on the
110 // current agent so freshly-registered extension tools become
111 // callable without restarting the rpc process.
112 adapter := &extToolAdapter{mgr: extMgr}
113 extMgr.SetOnReload(func() {
114 resolved, err := Resolve(args, true)
115 if err != nil {
116 return
117 }
118 resolved.MergeExtensionTools(adapter)
119 oldTools := ag.SetPromptConfig(resolved.SystemPrompt, resolved.ToolRegistry)
120 if closeErr := tools.CloseLSPManagers(oldTools); closeErr != nil {
121 fmt.Fprintln(os.Stderr, "reload LSP cleanup:", closeErr)
122 }
123 })
124
125 extMgr.EmitSessionEvent("session_start", nil, nil)
126
127 return server.run(os.Stdin)
128}
129
130// rpcExtHooks implements extensions.HostHooks for the headless RPC
131// loop. Notify and Display surface as `event` frames so any RPC
132// client can render them; Submit and Insert are no-ops because the
133// RPC loop has no editor and the prompt comes from the client.
134type rpcExtHooks struct {
135 server *rpcServer
136}
137
138func (h *rpcExtHooks) Notify(extName, level, message string) {
139 if h.server != nil {
140 h.server.writeExtensionEvent(map[string]any{
141 "type": "ext_notify",
142 "extension": extName,
143 "level": level,
144 "message": message,
145 })
146 }
147}
148func (h *rpcExtHooks) Alert(extName string, alert extproto.AlertRequest) {
149 if h.server != nil {
150 h.server.writeExtensionEvent(map[string]any{
151 "type": "ext_alert",
152 "extension": extName,
153 "kind": alert.Kind,
154 "reason": alert.Reason,
155 })
156 }
157}
158func (h *rpcExtHooks) Display(extName, text string) {
159 if h.server != nil {
160 h.server.writeExtensionEvent(map[string]any{
161 "type": "ext_display",
162 "extension": extName,
163 "text": text,
164 })
165 }
166}
167func (h *rpcExtHooks) ClearNotes(extName string) {
168 if h.server != nil {
169 h.server.writeExtensionEvent(map[string]any{
170 "type": "ext_clear_notes",
171 "extension": extName,
172 })
173 }
174}
175func (h *rpcExtHooks) Submit(string) {} // ignored in rpc mode
176func (h *rpcExtHooks) SubmitSlash(string) {} // ignored in rpc mode
177func (h *rpcExtHooks) Insert(string) {} // ignored in rpc mode
178func (h *rpcExtHooks) OpenPanel(string, extproto.PanelSpec) {}
179func (h *rpcExtHooks) UpdatePanel(string, string, string, []string, string) {}
180func (h *rpcExtHooks) ClosePanel(string, string) {}
181func (h *rpcExtHooks) SetStatus(extName, key, level, text string) {
182 if h.server != nil {
183 h.server.writeExtensionEvent(map[string]any{
184 "type": "ext_status", "extension": extName, "key": key, "level": level, "text": text,
185 })
186 }
187}
188func (h *rpcExtHooks) SetWidget(extName, id, position, title string, lines []string) {
189 if h.server != nil {
190 h.server.writeExtensionEvent(map[string]any{
191 "type": "ext_widget", "extension": extName, "id": id, "position": position, "title": title, "lines": lines,
192 })
193 }
194}
195func (h *rpcExtHooks) ClearWidget(extName, id string) {
196 if h.server != nil {
197 h.server.writeExtensionEvent(map[string]any{
198 "type": "ext_widget_clear", "extension": extName, "id": id,
199 })
200 }
201}
202
203func (h *rpcExtHooks) ClearExtensionChrome(extName string) {
204 if h.server != nil {
205 h.server.writeExtensionEvent(map[string]any{
206 "type": "ext_chrome_clear", "extension": extName,
207 })
208 }
209}
210
211const maxPendingRPCExtEvents = 64
212
213type rpcServer struct {
214 ctx context.Context
215 args Args
216 agent *core.Agent
217 provider string
218 model string
219 out io.Writer
220 version string
221
222 writeMu sync.Mutex
223 turnMu sync.Mutex // serialises one prompt at a time
224 activeCancel context.CancelFunc
225 started bool
226 authed bool
227 pendingExtEvents [][]byte
228
229 // inFlight tracks long-running command goroutines so run() can
230 // wait for them before returning when stdin closes. Without this,
231 // piping a single 'prompt' command into 'zut rpc' would race the
232 // process exit against the agent loop and the prompt would never
233 // produce output.
234 inFlight sync.WaitGroup
235}
236
237// run reads NDJSON commands from in and dispatches them. Returns when
238// in is closed AND every in-flight long-running command (prompt /
239// compact) has finished, so a quick `echo cmd | zut rpc` invocation
240// still produces full output before the process exits.
241func (s *rpcServer) run(in io.Reader) error {
242 requireToken := os.Getenv("ZUTCORE_RPC_TOKEN") != ""
243 s.writeMu.Lock()
244 s.started = true
245 s.authed = !requireToken
246 if s.authed {
247 s.flushPendingExtEventsLocked()
248 }
249 s.writeMu.Unlock()
250
251 sc := bufio.NewScanner(in)
252 sc.Buffer(make([]byte, 0, 64*1024), 16*1024*1024)
253 for sc.Scan() {
254 line := strings.TrimSpace(sc.Text())
255 if line == "" {
256 continue
257 }
258 var head struct {
259 Type string `json:"type"`
260 ID string `json:"id,omitempty"`
261 }
262 if err := json.Unmarshal([]byte(line), &head); err != nil {
263 s.writeError("", "", fmt.Sprintf("malformed json: %v", err))
264 continue
265 }
266 if !s.isAuthed() {
267 if head.Type != "hello" {
268 s.writeError(head.ID, head.Type, "auth required: send hello with token first")
269 continue
270 }
271 var hello struct {
272 Token string `json:"token"`
273 }
274 _ = json.Unmarshal([]byte(line), &hello)
275 if hello.Token != os.Getenv("ZUTCORE_RPC_TOKEN") {
276 s.writeError(head.ID, head.Type, "invalid token")
277 return fmt.Errorf("rpc: bad auth token")
278 }
279 s.authenticate(head.ID, head.Type)
280 continue
281 }
282 s.dispatch(head.Type, head.ID, []byte(line))
283 }
284 err := sc.Err()
285 s.inFlight.Wait()
286 return err
287}
288
289// dispatch routes a command. Long-running commands (prompt, compact)
290// run on their own goroutine so the read loop stays responsive.
291func (s *rpcServer) dispatch(cmd, id string, raw []byte) {
292 switch cmd {
293 case "hello":
294 s.writeResponse(id, cmd, map[string]any{
295 "protocol_version": 1,
296 "version": s.version,
297 "provider": s.provider,
298 "model": s.model,
299 })
300 case "prompt":
301 var req struct {
302 Message string `json:"message"`
303 Images []struct {
304 MimeType string `json:"mime_type"`
305 Data []byte `json:"data"`
306 } `json:"images"`
307 }
308 if err := json.Unmarshal(raw, &req); err != nil {
309 s.writeError(id, cmd, err.Error())
310 return
311 }
312 s.inFlight.Add(1)
313 go func() {
314 defer s.inFlight.Done()
315 s.runPrompt(id, req.Message, req.Images)
316 }()
317
318 case "abort":
319 if c := s.takeCancel(); c != nil {
320 c()
321 }
322 s.writeResponse(id, cmd, nil)
323
324 case "compact":
325 s.inFlight.Add(1)
326 go func() {
327 defer s.inFlight.Done()
328 s.runCompact(id)
329 }()
330
331 case "get_state":
332 s.writeResponse(id, cmd, s.snapshotState())
333
334 case "get_messages":
335 s.writeResponse(id, cmd, map[string]any{
336 "messages": messagesToJSON(s.agent.Messages()),
337 })
338
339 case "clear":
340 s.agent.SetMessages(nil)
341 s.writeResponse(id, cmd, nil)
342
343 case "set_model":
344 var req struct {
345 Model string `json:"model"`
346 }
347 if err := json.Unmarshal(raw, &req); err != nil {
348 s.writeError(id, cmd, err.Error())
349 return
350 }
351 if _, err := provider.FindModel(s.provider, req.Model); err != nil {
352 s.writeError(id, cmd, err.Error())
353 return
354 }
355 s.agent.Model = req.Model
356 s.model = req.Model
357 s.writeResponse(id, cmd, map[string]any{"model": req.Model})
358
359 case "set_reasoning":
360 var req struct {
361 Reasoning string `json:"reasoning"`
362 }
363 if err := json.Unmarshal(raw, &req); err != nil {
364 s.writeError(id, cmd, err.Error())
365 return
366 }
367 reasoning := provider.NormalizeReasoning(req.Reasoning)
368 switch reasoning {
369 case "", "minimum", "low", "medium", "high", "xhigh", "max":
370 default:
371 s.writeError(id, cmd, "reasoning must be off|minimum|low|medium|high|xhigh|max")
372 return
373 }
374 s.agent.Reasoning = reasoning
375 s.writeResponse(id, cmd, map[string]any{"reasoning": reasoning})
376
377 case "get_models":
378 out := []map[string]any{}
379 for _, m := range provider.ModelsForProvider(s.provider) {
380 out = append(out, map[string]any{
381 "id": m.ID,
382 "provider": m.Provider,
383 "context_window": m.ContextWindow,
384 "max_output": m.MaxOutput,
385 "reasoning": m.Reasoning,
386 })
387 }
388 s.writeResponse(id, cmd, map[string]any{"models": out})
389
390 case "ping":
391 s.writeResponse(id, cmd, map[string]any{"pong": true})
392
393 default:
394 s.writeError(id, cmd, "unknown command")
395 }
396}
397
398// runPrompt executes a single prompt turn and streams events out.
399// Holds turnMu so a second concurrent prompt blocks until this one
400// finishes; the user can abort with the abort command.
401func (s *rpcServer) runPrompt(id, message string, images []struct {
402 MimeType string `json:"mime_type"`
403 Data []byte `json:"data"`
404}) {
405 s.turnMu.Lock()
406 defer s.turnMu.Unlock()
407
408 subCtx, cancel := context.WithCancel(s.ctx)
409 s.setCancel(cancel)
410 defer s.setCancel(nil)
411
412 s.writeResponse(id, "prompt", map[string]any{"started": true})
413
414 imgs := make([]provider.ImageBlock, 0, len(images))
415 for _, im := range images {
416 imgs = append(imgs, provider.ImageBlock{MimeType: im.MimeType, Data: im.Data})
417 }
418
419 err := s.agent.Prompt(subCtx, message, imgs, func(ev core.AgentEvent) {
420 // EvDone is emitted by the agent loop and we re-emit our own
421 // 'done' below; suppressing it here avoids duplicate frames.
422 if _, ok := ev.(core.EvDone); ok {
423 return
424 }
425 s.writeEvent(modes.EventToJSON(ev))
426 })
427 // Don't emit a stand-alone error event for cancellation; the prior
428 // turn_end with stop=aborted already carries that signal.
429 if err != nil && !errors.Is(err, context.Canceled) {
430 s.writeEvent(map[string]any{"type": "error", "message": err.Error()})
431 }
432 s.writeEvent(map[string]any{"type": "done"})
433}
434
435// runCompact mirrors runPrompt but for compaction.
436func (s *rpcServer) runCompact(id string) {
437 s.turnMu.Lock()
438 defer s.turnMu.Unlock()
439
440 subCtx, cancel := context.WithCancel(s.ctx)
441 s.setCancel(cancel)
442 defer s.setCancel(nil)
443
444 s.writeResponse(id, "compact", map[string]any{"started": true})
445 summary, err := s.agent.CompactWithEvents(subCtx, 4, func(ev core.AgentEvent) {
446 s.writeEvent(modes.EventToJSON(ev))
447 })
448 if err != nil {
449 if !errors.Is(err, context.Canceled) {
450 s.writeEvent(map[string]any{"type": "error", "message": err.Error()})
451 }
452 return
453 }
454 s.writeEvent(map[string]any{
455 "type": "compact_done",
456 "summary": summary,
457 })
458}
459
460// snapshotState builds the get_state response.
461func (s *rpcServer) snapshotState() map[string]any {
462 cum := s.agent.Cost()
463 return map[string]any{
464 "provider": s.provider,
465 "model": s.model,
466 "reasoning": s.agent.Reasoning,
467 "cwd": s.args.CWD,
468 "message_count": len(s.agent.Messages()),
469 "busy": s.activeCancel != nil,
470 "usage": map[string]any{
471 "input": cum.InputTokens,
472 "output": cum.OutputTokens,
473 "reasoning": rpcReasoningTokens(cum),
474 "cache_read": cum.CacheReadTokens,
475 "cache_write": cum.CacheWriteTokens,
476 "cost_usd": cum.CostUSD,
477 },
478 }
479}
480
481func rpcReasoningTokens(usage provider.Usage) any {
482 if !usage.ReasoningTokensKnown {
483 return nil
484 }
485 return usage.ReasoningTokens
486}
487
488// ---- write helpers (single-line JSON, mutex-guarded) ----
489
490func (s *rpcServer) writeResponse(id, cmd string, data any) {
491 frame := map[string]any{
492 "type": "response",
493 "command": cmd,
494 "success": true,
495 }
496 if id != "" {
497 frame["id"] = id
498 }
499 if data != nil {
500 frame["data"] = data
501 }
502 s.write(frame)
503}
504
505func (s *rpcServer) writeError(id, cmd, msg string) {
506 frame := map[string]any{
507 "type": "response",
508 "command": cmd,
509 "success": false,
510 "error": msg,
511 }
512 if id != "" {
513 frame["id"] = id
514 }
515 s.write(frame)
516}
517
518func (s *rpcServer) writeEvent(payload map[string]any) {
519 s.write(payload)
520}
521
522func (s *rpcServer) writeExtensionEvent(payload map[string]any) {
523 b, err := json.Marshal(payload)
524 if err != nil {
525 return
526 }
527 s.writeMu.Lock()
528 defer s.writeMu.Unlock()
529 if !s.started || !s.authed {
530 if len(s.pendingExtEvents) < maxPendingRPCExtEvents {
531 s.pendingExtEvents = append(s.pendingExtEvents, b)
532 }
533 return
534 }
535 s.writeLocked(b)
536}
537
538func (s *rpcServer) flushPendingExtEventsLocked() {
539 for _, b := range s.pendingExtEvents {
540 s.writeLocked(b)
541 }
542 s.pendingExtEvents = nil
543}
544
545func (s *rpcServer) isAuthed() bool {
546 s.writeMu.Lock()
547 defer s.writeMu.Unlock()
548 return s.authed
549}
550
551func (s *rpcServer) authenticate(id, cmd string) {
552 frame := map[string]any{
553 "type": "response",
554 "command": cmd,
555 "success": true,
556 "data": map[string]any{
557 "protocol_version": 1,
558 "version": s.version,
559 "provider": s.provider,
560 "model": s.model,
561 },
562 }
563 if id != "" {
564 frame["id"] = id
565 }
566 b, err := json.Marshal(frame)
567 if err != nil {
568 return
569 }
570 s.writeMu.Lock()
571 defer s.writeMu.Unlock()
572 s.authed = true
573 s.writeLocked(b)
574 s.flushPendingExtEventsLocked()
575}
576
577func (s *rpcServer) write(v any) {
578 b, err := json.Marshal(v)
579 if err != nil {
580 return
581 }
582 s.writeMu.Lock()
583 defer s.writeMu.Unlock()
584 s.writeLocked(b)
585}
586
587func (s *rpcServer) writeLocked(b []byte) {
588 _, _ = s.out.Write(b)
589 _, _ = s.out.Write([]byte("\n"))
590}
591
592func (s *rpcServer) setCancel(c context.CancelFunc) {
593 s.writeMu.Lock()
594 s.activeCancel = c
595 s.writeMu.Unlock()
596}
597
598func (s *rpcServer) takeCancel() context.CancelFunc {
599 s.writeMu.Lock()
600 defer s.writeMu.Unlock()
601 c := s.activeCancel
602 s.activeCancel = nil
603 return c
604}
605
606// messagesToJSON serialises a transcript using the same schema as the
607// --json event mode for cross-format consistency.
608func messagesToJSON(msgs []provider.Message) []map[string]any {
609 out := make([]map[string]any, 0, len(msgs))
610 for _, m := range msgs {
611 out = append(out, map[string]any{
612 "role": string(m.Role),
613 "content": modes.ContentToJSON(m.Content),
614 "time": m.Time,
615 })
616 }
617 return out
618}