fix(subagents): recover from context limits

commit: 1c1fef041685b6719ec9d30db55c2f7fc7ec5f35
author: brice · 2mo ago · 2026-08-06 08:42 UTC
committer: brice · 2mo ago · 2026-08-06 09:18 UTC
parent: 42a5079
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

8 files · +490 -51

M docs/subagents.md +2 -0


@@ -94,6 +94,8 @@ The worker and supervisor communicate over newline-delimited JSON. Current messa
94	94
95	95		A completed worker emits a `turn.result` event and writes `result.json`. The inline output is bounded; inspect the full session through the stable references:
96	96
	97	+	If a provider rejects a child request because its payload or context window is too large, the worker compacts its persisted transcript and continues the same request once. If compaction or that retry cannot fit, the result uses error code `context_limit` and directs the caller to narrow the task or reduce gathered context; it does not include the provider's raw request error.
	98	+
97	99		```text
98	100		subagent://<id>
99	101		subagent://<id>/history


@@ -94,6 +94,8 @@ The worker and supervisor communicate over newline-delimited JSON. Current messa
94		94
95	A completed worker emits a `turn.result` event and writes `result.json`. The inline output is bounded; inspect the full session through the stable references:	95		A completed worker emits a `turn.result` event and writes `result.json`. The inline output is bounded; inspect the full session through the stable references:
96		96
		97	+	If a provider rejects a child request because its payload or context window is too large, the worker compacts its persisted transcript and continues the same request once. If compaction or that retry cannot fit, the result uses error code `context_limit` and directs the caller to narrow the task or reduce gathered context; it does not include the provider's raw request error.
		98	+
97	```text	99		```text
98	subagent://<id>	100		subagent://<id>
99	subagent://<id>/history	101		subagent://<id>/history

M packages/agent/modes/compact_queue_test.go +0 -24


@@ -430,30 +430,6 @@ func TestContextWindowRecoveryStopsAfterOneRetry(t *testing.T) {
430	430		}
431	431		}
432	432
433		-	func TestContextOverflowErrorRecognizesProviderMessages(t *testing.T) {
434		-	tests := []struct {
435		-	name string
436		-	err error
437		-	want bool
438		-	}{
439		-	{name: "http 413", err: errors.New("provider http 413: request rejected"), want: true},
440		-	{name: "context error code", err: errors.New("context_length_exceeded"), want: true},
441		-	{name: "maximum context length", err: errors.New("This model's maximum context length is 128000 tokens"), want: true},
442		-	{name: "context window exceeded", err: errors.New("context window exceeded"), want: true},
443		-	{name: "maximum input token count", err: errors.New("input token count exceeds the maximum number of tokens allowed"), want: true},
444		-	{name: "maximum output token count", err: errors.New("max_tokens exceeds the maximum number of tokens allowed"), want: false},
445		-	{name: "unrelated error", err: errors.New("rate limit exceeded"), want: false},
446		-	}
447		-
448		-	for _, tt := range tests {
449		-	t.Run(tt.name, func(t *testing.T) {
450		-	if got := isContextOverflowError(tt.err); got != tt.want {
451		-	t.Fatalf("isContextOverflowError(%q) = %t, want %t", tt.err, got, tt.want)
452		-	}
453		-	})
454		-	}
455		-	}
456		-
457	433		func requestContainsUserText(req provider.Request, want string) bool {
458	434		return requestUserTextCount(req, want) > 0
459	435		}


@@ -430,30 +430,6 @@ func TestContextWindowRecoveryStopsAfterOneRetry(t *testing.T) {
430		}	430	}
431		}	431	}
432			432
433	-	func TestContextOverflowErrorRecognizesProviderMessages(t *testing.T) {
434	-	tests := []struct {
435	-	name string
436	-	err error
437	-	want bool
438	-	}{
439	-	{name: "http 413", err: errors.New("provider http 413: request rejected"), want: true},
440	-	{name: "context error code", err: errors.New("context_length_exceeded"), want: true},
441	-	{name: "maximum context length", err: errors.New("This model's maximum context length is 128000 tokens"), want: true},
442	-	{name: "context window exceeded", err: errors.New("context window exceeded"), want: true},
443	-	{name: "maximum input token count", err: errors.New("input token count exceeds the maximum number of tokens allowed"), want: true},
444	-	{name: "maximum output token count", err: errors.New("max_tokens exceeds the maximum number of tokens allowed"), want: false},
445	-	{name: "unrelated error", err: errors.New("rate limit exceeded"), want: false},
446	-	}
447	-
448	-	for _, tt := range tests {
449	-	t.Run(tt.name, func(t *testing.T) {
450	-	if got := isContextOverflowError(tt.err); got != tt.want {
451	-	t.Fatalf("isContextOverflowError(%q) = %t, want %t", tt.err, got, tt.want)
452	-	}
453	-	})
454	-	}
455	-	}
456	-
457		func requestContainsUserText(req provider.Request, want string) bool {	433	func requestContainsUserText(req provider.Request, want string) bool {
458		return requestUserTextCount(req, want) > 0	434	return requestUserTextCount(req, want) > 0
459		}	435	}

M packages/agent/modes/interactive.go +1 -22


@@ -6859,7 +6859,7 @@ func (i *Interactive) startTurnRequest(parent context.Context, prompt string, im
6859	6859		// based auto-compact can miss both when metadata is stale or the
6860	6860		// limit is measured in raw bytes. Compact once, then continue the
6861	6861		// user message already present in the transcript.
6862		-	contextOverflow := err != nil && ctx.Err() == nil && isContextOverflowError(err)
	6862	+	contextOverflow := err != nil && ctx.Err() == nil && provider.IsContextOverflowError(err)
6863	6863		recoverContextOverflow := contextOverflow && !overflowRecoveryAttempted
6864	6864		if recoverContextOverflow {
6865	6865		i.statusErr = ""

@@ -7033,27 +7033,6 @@ func autoCompactNoteLine(th tui.Theme, msg string) string {
7033	7033		return " " + th.FGColor(th.Warning, "⚠ "+msg)
7034	7034		}
7035	7035
7036		-	// isContextOverflowError matches provider responses that reject the
7037		-	// current request because its raw payload or tokenized input is too
7038		-	// large. Providers surface this as either HTTP 413 or semantic context
7039		-	// errors with differing codes and messages.
7040		-	func isContextOverflowError(err error) bool {
7041		-	if err == nil {
7042		-	return false
7043		-	}
7044		-	msg := strings.ToLower(err.Error())
7045		-	return strings.Contains(msg, "http 413") \|\|
7046		-	strings.Contains(msg, " 413") \|\|
7047		-	strings.HasPrefix(msg, "413 ") \|\|
7048		-	strings.Contains(msg, "payload too large") \|\|
7049		-	strings.Contains(msg, "request entity too large") \|\|
7050		-	strings.Contains(msg, "input exceeds the context window") \|\|
7051		-	strings.Contains(msg, "context window exceeded") \|\|
7052		-	strings.Contains(msg, "maximum context length") \|\|
7053		-	strings.Contains(msg, "context_length_exceeded") \|\|
7054		-	(strings.Contains(msg, "input") && strings.Contains(msg, "exceeds the maximum number of tokens"))
7055		-	}
7056		-
7057	7036		const defaultAutoCompactThreshold = 85
7058	7037
7059	7038		func normalizeAutoCompactThreshold(threshold *int) int {


@@ -6859,7 +6859,7 @@ func (i *Interactive) startTurnRequest(parent context.Context, prompt string, im
6859		// based auto-compact can miss both when metadata is stale or the	6859		// based auto-compact can miss both when metadata is stale or the
6860		// limit is measured in raw bytes. Compact once, then continue the	6860		// limit is measured in raw bytes. Compact once, then continue the
6861		// user message already present in the transcript.	6861		// user message already present in the transcript.
6862	-	contextOverflow := err != nil && ctx.Err() == nil && isContextOverflowError(err)	6862	+	contextOverflow := err != nil && ctx.Err() == nil && provider.IsContextOverflowError(err)
6863		recoverContextOverflow := contextOverflow && !overflowRecoveryAttempted	6863		recoverContextOverflow := contextOverflow && !overflowRecoveryAttempted
6864		if recoverContextOverflow {	6864		if recoverContextOverflow {
6865		i.statusErr = ""	6865		i.statusErr = ""

@@ -7033,27 +7033,6 @@ func autoCompactNoteLine(th tui.Theme, msg string) string {
7033		return " " + th.FGColor(th.Warning, "⚠ "+msg)	7033		return " " + th.FGColor(th.Warning, "⚠ "+msg)
7034		}	7034		}
7035			7035
7036	-	// isContextOverflowError matches provider responses that reject the
7037	-	// current request because its raw payload or tokenized input is too
7038	-	// large. Providers surface this as either HTTP 413 or semantic context
7039	-	// errors with differing codes and messages.
7040	-	func isContextOverflowError(err error) bool {
7041	-	if err == nil {
7042	-	return false
7043	-	}
7044	-	msg := strings.ToLower(err.Error())
7045	-	return strings.Contains(msg, "http 413") \|\|
7046	-	strings.Contains(msg, " 413") \|\|
7047	-	strings.HasPrefix(msg, "413 ") \|\|
7048	-	strings.Contains(msg, "payload too large") \|\|
7049	-	strings.Contains(msg, "request entity too large") \|\|
7050	-	strings.Contains(msg, "input exceeds the context window") \|\|
7051	-	strings.Contains(msg, "context window exceeded") \|\|
7052	-	strings.Contains(msg, "maximum context length") \|\|
7053	-	strings.Contains(msg, "context_length_exceeded") \|\|
7054	-	(strings.Contains(msg, "input") && strings.Contains(msg, "exceeds the maximum number of tokens"))
7055	-	}
7056	-
7057		const defaultAutoCompactThreshold = 85	7036		const defaultAutoCompactThreshold = 85
7058			7037
7059		func normalizeAutoCompactThreshold(threshold *int) int {	7038		func normalizeAutoCompactThreshold(threshold *int) int {

M packages/agent/modes/rescue_dialog.go +1 -1


@@ -233,7 +233,7 @@ func classifyRescueError(err error) (bool, string) {
233	233
234	234		// Don't trigger on context overflow; that path already has its own
235	235		// auto-compact handling.
236		-	if isContextOverflowError(err) {
	236	+	if provider.IsContextOverflowError(err) {
237	237		return false, ""
238	238		}
239	239


@@ -233,7 +233,7 @@ func classifyRescueError(err error) (bool, string) {
233			233
234		// Don't trigger on context overflow; that path already has its own	234		// Don't trigger on context overflow; that path already has its own
235		// auto-compact handling.	235		// auto-compact handling.
236	-	if isContextOverflowError(err) {	236	+	if provider.IsContextOverflowError(err) {
237		return false, ""	237		return false, ""
238		}	238		}
239			239

M packages/agent/subagent_worker.go +67 -4


@@ -201,11 +201,14 @@ func runSubagentWorkerMode(ctx context.Context, args Args, version string) error
201	201		em.emit("turn.started", map[string]any{"step": step, "turn_id": turnID})
202	202
203	203		sink := func(ev core.AgentEvent) {
204		-	em.emit(ev.Type(), modes.EventToJSON(ev))
	204	+	em.emit(ev.Type(), subagentEventData(ev))
205	205		}
206	206
207		-	start := len(ag.Messages())
208		-	err := ag.Prompt(c, prompt, nil, sink)
	207	+	var persistCompaction func([]provider.Message) error
	208	+	if sess != nil {
	209	+	persistCompaction = sess.AppendCompaction
	210	+	}
	211	+	start, err := promptWithContextRecovery(c, ag, prompt, sink, persistCompaction)
209	212		WriteNewTranscript(ag, sess, start)
210	213
211	214		output := finalAssistantText(ag.Messages()[start:])

@@ -231,7 +234,7 @@ func runSubagentWorkerMode(ctx context.Context, args Args, version string) error
231	234		em.emit("turn_end", map[string]any{
232	235		"step": step,
233	236		"turn_id": turnID,
234		-	"error": errString(err),
	237	+	"error": turnErrorMessage(err),
235	238		})
236	239		em.emit("agent.idle", map[string]any{"turn_id": turnID})
237	240

@@ -402,6 +405,14 @@ func (e *subagentEmitter) emit(typ string, data map[string]any) {
402	405		}
403	406		}
404	407
	408	+	func subagentEventData(ev core.AgentEvent) map[string]any {
	409	+	data := modes.EventToJSON(ev)
	410	+	if turnEnd, ok := ev.(core.EvTurnEnd); ok && provider.IsContextOverflowError(turnEnd.Err) {
	411	+	data["error"] = subagentContextLimitMessage
	412	+	}
	413	+	return data
	414	+	}
	415	+
405	416		func canonicalWorkerEvent(typ string) string {
406	417		switch typ {
407	418		case "agent_ready":

@@ -423,6 +434,48 @@ func canonicalWorkerEvent(typ string) string {
423	434		}
424	435		}
425	436
	437	+	const subagentContextLimitMessage = "request exceeds the model context window; narrow the task or reduce gathered context"
	438	+
	439	+	// promptWithContextRecovery appends prompt and runs it once. When the provider
	440	+	// rejects that request for exceeding its context limit, it compacts the current
	441	+	// transcript and continues the already-appended prompt exactly once.
	442	+	//
	443	+	// The returned index marks the first message that can contribute to the turn
	444	+	// result or be appended after a compaction checkpoint. Compact replaces the
	445	+	// transcript, so callers must not reuse the index captured before Prompt.
	446	+	func promptWithContextRecovery(ctx context.Context, ag *core.Agent, prompt string, sink func(core.AgentEvent), persistCompaction func([]provider.Message) error) (outputStart int, err error) {
	447	+	outputStart = len(ag.Messages())
	448	+	if err = ag.Prompt(ctx, prompt, nil, sink); err == nil \|\| ctx.Err() != nil \|\| !provider.IsContextOverflowError(err) {
	449	+	return outputStart, err
	450	+	}
	451	+
	452	+	messages := ag.Messages()
	453	+	if len(messages) <= 1 {
	454	+	// The only message is the failed prompt. Summarizing it would replace
	455	+	// the user's task with an LLM-generated paraphrase, so report the
	456	+	// provider's limit and ask the caller to narrow the task instead.
	457	+	return outputStart, err
	458	+	}
	459	+	keepTail := min(4, len(messages)-1)
	460	+	if _, compactErr := ag.Compact(ctx, keepTail, nil); compactErr != nil {
	461	+	return outputStart, fmt.Errorf("compact transcript after initial overflow: %w", compactErr)
	462	+	}
	463	+
	464	+	compacted := ag.Messages()
	465	+	if persistCompaction != nil {
	466	+	if persistErr := persistCompaction(compacted); persistErr != nil {
	467	+	// Keep the original history plus the user's pending task so the
	468	+	// outer transcript flush can persist that task without committing
	469	+	// an in-memory compaction that the session did not receive.
	470	+	ag.SetMessages(messages)
	471	+	return outputStart, fmt.Errorf("persist compacted transcript: %w", persistErr)
	472	+	}
	473	+	}
	474	+
	475	+	outputStart = len(compacted)
	476	+	return outputStart, ag.Continue(ctx, sink)
	477	+	}
	478	+
426	479		func finalAssistantText(messages []provider.Message) string {
427	480		var out strings.Builder
428	481		for _, message := range messages {

@@ -498,9 +551,19 @@ func resultErrorPayload(err error) map[string]any {
498	551		if err == nil {
499	552		return nil
500	553		}
	554	+	if provider.IsContextOverflowError(err) {
	555	+	return map[string]any{"code": "context_limit", "message": subagentContextLimitMessage}
	556	+	}
501	557		return map[string]any{"code": "turn_failed", "message": truncateForLog(err.Error(), 500)}
502	558		}
503	559
	560	+	func turnErrorMessage(err error) string {
	561	+	if provider.IsContextOverflowError(err) {
	562	+	return subagentContextLimitMessage
	563	+	}
	564	+	return errString(err)
	565	+	}
	566	+
504	567		func errString(err error) string {
505	568		if err == nil {
506	569		return ""


@@ -201,11 +201,14 @@ func runSubagentWorkerMode(ctx context.Context, args Args, version string) error
201		em.emit("turn.started", map[string]any{"step": step, "turn_id": turnID})	201		em.emit("turn.started", map[string]any{"step": step, "turn_id": turnID})
202			202
203		sink := func(ev core.AgentEvent) {	203		sink := func(ev core.AgentEvent) {
204	-	em.emit(ev.Type(), modes.EventToJSON(ev))	204	+	em.emit(ev.Type(), subagentEventData(ev))
205		}	205		}
206			206
207	-	start := len(ag.Messages())	207	+	var persistCompaction func([]provider.Message) error
208	-	err := ag.Prompt(c, prompt, nil, sink)	208	+	if sess != nil {
			209	+	persistCompaction = sess.AppendCompaction
			210	+	}
			211	+	start, err := promptWithContextRecovery(c, ag, prompt, sink, persistCompaction)
209		WriteNewTranscript(ag, sess, start)	212		WriteNewTranscript(ag, sess, start)
210			213
211		output := finalAssistantText(ag.Messages()[start:])	214		output := finalAssistantText(ag.Messages()[start:])

@@ -231,7 +234,7 @@ func runSubagentWorkerMode(ctx context.Context, args Args, version string) error
231		em.emit("turn_end", map[string]any{	234		em.emit("turn_end", map[string]any{
232		"step": step,	235		"step": step,
233		"turn_id": turnID,	236		"turn_id": turnID,
234	-	"error": errString(err),	237	+	"error": turnErrorMessage(err),
235		})	238		})
236		em.emit("agent.idle", map[string]any{"turn_id": turnID})	239		em.emit("agent.idle", map[string]any{"turn_id": turnID})
237			240

@@ -402,6 +405,14 @@ func (e *subagentEmitter) emit(typ string, data map[string]any) {
402		}	405		}
403		}	406		}
404			407
			408	+	func subagentEventData(ev core.AgentEvent) map[string]any {
			409	+	data := modes.EventToJSON(ev)
			410	+	if turnEnd, ok := ev.(core.EvTurnEnd); ok && provider.IsContextOverflowError(turnEnd.Err) {
			411	+	data["error"] = subagentContextLimitMessage
			412	+	}
			413	+	return data
			414	+	}
			415	+
405		func canonicalWorkerEvent(typ string) string {	416		func canonicalWorkerEvent(typ string) string {
406		switch typ {	417		switch typ {
407		case "agent_ready":	418		case "agent_ready":

@@ -423,6 +434,48 @@ func canonicalWorkerEvent(typ string) string {
423		}	434		}
424		}	435		}
425			436
			437	+	const subagentContextLimitMessage = "request exceeds the model context window; narrow the task or reduce gathered context"
			438	+
			439	+	// promptWithContextRecovery appends prompt and runs it once. When the provider
			440	+	// rejects that request for exceeding its context limit, it compacts the current
			441	+	// transcript and continues the already-appended prompt exactly once.
			442	+	//
			443	+	// The returned index marks the first message that can contribute to the turn
			444	+	// result or be appended after a compaction checkpoint. Compact replaces the
			445	+	// transcript, so callers must not reuse the index captured before Prompt.
			446	+	func promptWithContextRecovery(ctx context.Context, ag *core.Agent, prompt string, sink func(core.AgentEvent), persistCompaction func([]provider.Message) error) (outputStart int, err error) {
			447	+	outputStart = len(ag.Messages())
			448	+	if err = ag.Prompt(ctx, prompt, nil, sink); err == nil \|\| ctx.Err() != nil \|\| !provider.IsContextOverflowError(err) {
			449	+	return outputStart, err
			450	+	}
			451	+
			452	+	messages := ag.Messages()
			453	+	if len(messages) <= 1 {
			454	+	// The only message is the failed prompt. Summarizing it would replace
			455	+	// the user's task with an LLM-generated paraphrase, so report the
			456	+	// provider's limit and ask the caller to narrow the task instead.
			457	+	return outputStart, err
			458	+	}
			459	+	keepTail := min(4, len(messages)-1)
			460	+	if _, compactErr := ag.Compact(ctx, keepTail, nil); compactErr != nil {
			461	+	return outputStart, fmt.Errorf("compact transcript after initial overflow: %w", compactErr)
			462	+	}
			463	+
			464	+	compacted := ag.Messages()
			465	+	if persistCompaction != nil {
			466	+	if persistErr := persistCompaction(compacted); persistErr != nil {
			467	+	// Keep the original history plus the user's pending task so the
			468	+	// outer transcript flush can persist that task without committing
			469	+	// an in-memory compaction that the session did not receive.
			470	+	ag.SetMessages(messages)
			471	+	return outputStart, fmt.Errorf("persist compacted transcript: %w", persistErr)
			472	+	}
			473	+	}
			474	+
			475	+	outputStart = len(compacted)
			476	+	return outputStart, ag.Continue(ctx, sink)
			477	+	}
			478	+
426		func finalAssistantText(messages []provider.Message) string {	479		func finalAssistantText(messages []provider.Message) string {
427		var out strings.Builder	480		var out strings.Builder
428		for _, message := range messages {	481		for _, message := range messages {

@@ -498,9 +551,19 @@ func resultErrorPayload(err error) map[string]any {
498		if err == nil {	551		if err == nil {
499		return nil	552		return nil
500		}	553		}
			554	+	if provider.IsContextOverflowError(err) {
			555	+	return map[string]any{"code": "context_limit", "message": subagentContextLimitMessage}
			556	+	}
501		return map[string]any{"code": "turn_failed", "message": truncateForLog(err.Error(), 500)}	557		return map[string]any{"code": "turn_failed", "message": truncateForLog(err.Error(), 500)}
502		}	558		}
503			559
			560	+	func turnErrorMessage(err error) string {
			561	+	if provider.IsContextOverflowError(err) {
			562	+	return subagentContextLimitMessage
			563	+	}
			564	+	return errString(err)
			565	+	}
			566	+
504		func errString(err error) string {	567		func errString(err error) string {
505		if err == nil {	568		if err == nil {
506		return ""	569		return ""

M packages/agent/subagent_worker_test.go +340 -0


@@ -2,14 +2,19 @@ package agent
2	2
3	3		import (
4	4		"bytes"
	5	+	"context"
5	6		"encoding/json"
	7	+	"errors"
6	8		"io"
7	9		"os"
8	10		"path/filepath"
9	11		"strings"
	12	+	"sync"
10	13		"testing"
11	14
12	15		"github.com/bnema/zut/packages/agent/subagents"
	16	+	"github.com/bnema/zut/packages/core"
	17	+	"github.com/bnema/zut/packages/provider"
13	18		)
14	19
15	20		// TestWorkerOutputLimitsUseSupervisorPolicy verifies that the child reads

@@ -30,6 +35,341 @@ func TestWorkerOutputLimitsUseSupervisorPolicy(t *testing.T) {
30	35		}
31	36		}
32	37
	38	+	type subagentContextRecoveryClient struct {
	39	+	mu sync.Mutex
	40	+	calls int
	41	+	requests []provider.Request
	42	+	retried chan provider.Request
	43	+	compactionErr error
	44	+	retryOverflow bool
	45	+	}
	46	+
	47	+	func (c *subagentContextRecoveryClient) Name() string { return "subagent-context-recovery-test" }
	48	+
	49	+	func (c *subagentContextRecoveryClient) Stream(_ context.Context, req provider.Request) (<-chan provider.Event, error) {
	50	+	c.mu.Lock()
	51	+	c.calls++
	52	+	call := c.calls
	53	+	c.requests = append(c.requests, req)
	54	+	c.mu.Unlock()
	55	+
	56	+	events := make(chan provider.Event, 2)
	57	+	go func() {
	58	+	defer close(events)
	59	+	switch call {
	60	+	case 1:
	61	+	events <- provider.EventDone{Stop: provider.StopError, Err: errors.New("provider error: input exceeds the context window")}
	62	+	case 2:
	63	+	if c.compactionErr != nil {
	64	+	events <- provider.EventDone{Stop: provider.StopError, Err: c.compactionErr}
	65	+	return
	66	+	}
	67	+	events <- provider.EventTextDelta{Delta: "summary"}
	68	+	events <- provider.EventDone{Stop: provider.StopEnd}
	69	+	default:
	70	+	c.retried <- req
	71	+	if c.retryOverflow {
	72	+	events <- provider.EventDone{Stop: provider.StopError, Err: errors.New("context window exceeded after compaction")}
	73	+	return
	74	+	}
	75	+	events <- provider.EventDone{Stop: provider.StopEnd, Message: provider.Message{
	76	+	Role: provider.RoleAssistant,
	77	+	Content: []provider.Content{provider.TextBlock{Text: "recovered"}},
	78	+	}}
	79	+	}
	80	+	}()
	81	+	return events, nil
	82	+	}
	83	+
	84	+	func TestPromptWithContextRecoveryCompactsAndContinues(t *testing.T) {
	85	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
	86	+	agent := core.NewAgent(client, "test-model", "", nil)
	87	+	agent.SetMessages([]provider.Message{
	88	+	{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "one"}}},
	89	+	{Role: provider.RoleAssistant, Content: []provider.Content{provider.TextBlock{Text: "two"}}},
	90	+	{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "three"}}},
	91	+	{Role: provider.RoleAssistant, Content: []provider.Content{provider.TextBlock{Text: "four"}}},
	92	+	})
	93	+
	94	+	outputStart, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, nil)
	95	+	if err != nil {
	96	+	t.Fatalf("promptWithContextRecovery returned %v", err)
	97	+	}
	98	+	if got := finalAssistantText(agent.Messages()[outputStart:]); got != "recovered" {
	99	+	t.Fatalf("final assistant text = %q, want recovered", got)
	100	+	}
	101	+
	102	+	request := <-client.retried
	103	+	if got := workerRequestUserTextCount(request, "finish the task"); got != 1 {
	104	+	t.Fatalf("retried request contains prompt %d times, want 1: %#v", got, request.Messages)
	105	+	}
	106	+	client.mu.Lock()
	107	+	calls := client.calls
	108	+	requests := append([]provider.Request(nil), client.requests...)
	109	+	client.mu.Unlock()
	110	+	if calls != 3 \|\| len(requests) != 3 {
	111	+	t.Fatalf("provider calls/requests = %d/%d, want 3/3", calls, len(requests))
	112	+	}
	113	+	if !workerRequestContainsText(requests[1], "<conversation>") \|\| !workerRequestContainsText(requests[1], "one") {
	114	+	t.Fatalf("compaction request does not include the older transcript: %#v", requests[1].Messages)
	115	+	}
	116	+	}
	117	+
	118	+	func TestPromptWithContextRecoveryStopsAfterOneRetry(t *testing.T) {
	119	+	client := &subagentContextRecoveryClient{
	120	+	retried: make(chan provider.Request, 1),
	121	+	retryOverflow: true,
	122	+	}
	123	+	agent := core.NewAgent(client, "test-model", "", nil)
	124	+	agent.SetMessages([]provider.Message{{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "prior context"}}}})
	125	+
	126	+	_, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, nil)
	127	+	if !provider.IsContextOverflowError(err) {
	128	+	t.Fatalf("promptWithContextRecovery error = %v, want context overflow", err)
	129	+	}
	130	+	<-client.retried
	131	+	client.mu.Lock()
	132	+	calls := client.calls
	133	+	client.mu.Unlock()
	134	+	if calls != 3 {
	135	+	t.Fatalf("provider calls = %d, want one initial prompt, compaction, and one continuation", calls)
	136	+	}
	137	+	}
	138	+
	139	+	func TestPromptWithContextRecoveryDoesNotCompactAfterCancellation(t *testing.T) {
	140	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
	141	+	agent := core.NewAgent(client, "test-model", "", nil)
	142	+	agent.SetMessages([]provider.Message{{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "prior context"}}}})
	143	+	ctx, cancel := context.WithCancel(context.Background())
	144	+	defer cancel()
	145	+
	146	+	_, err := promptWithContextRecovery(ctx, agent, "finish the task", func(event core.AgentEvent) {
	147	+	if turnEnd, ok := event.(core.EvTurnEnd); ok && provider.IsContextOverflowError(turnEnd.Err) {
	148	+	cancel()
	149	+	}
	150	+	}, nil)
	151	+	if !provider.IsContextOverflowError(err) {
	152	+	t.Fatalf("promptWithContextRecovery error = %v, want context overflow", err)
	153	+	}
	154	+	if err := ctx.Err(); !errors.Is(err, context.Canceled) {
	155	+	t.Fatalf("context error = %v, want %v", err, context.Canceled)
	156	+	}
	157	+	client.mu.Lock()
	158	+	calls := client.calls
	159	+	client.mu.Unlock()
	160	+	if calls != 1 {
	161	+	t.Fatalf("provider calls = %d, want only the initial prompt after cancellation", calls)
	162	+	}
	163	+	}
	164	+
	165	+	func TestPromptWithContextRecoveryPropagatesCompactionFailure(t *testing.T) {
	166	+	client := &subagentContextRecoveryClient{
	167	+	retried: make(chan provider.Request, 1),
	168	+	compactionErr: errors.New("compaction provider unavailable"),
	169	+	}
	170	+	agent := core.NewAgent(client, "test-model", "", nil)
	171	+	agent.SetMessages([]provider.Message{{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "prior context"}}}})
	172	+
	173	+	_, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, nil)
	174	+	if err == nil \|\| !strings.Contains(err.Error(), "compact transcript after initial overflow") {
	175	+	t.Fatalf("promptWithContextRecovery error = %v, want compaction failure", err)
	176	+	}
	177	+	payload := resultErrorPayload(err)
	178	+	if payload["code"] != "turn_failed" {
	179	+	t.Fatalf("result error payload = %#v, want turn_failed", payload)
	180	+	}
	181	+	}
	182	+
	183	+	func TestPromptWithContextRecoveryKeepsSinglePromptIntact(t *testing.T) {
	184	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
	185	+	agent := core.NewAgent(client, "test-model", "", nil)
	186	+
	187	+	_, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, nil)
	188	+	if !provider.IsContextOverflowError(err) {
	189	+	t.Fatalf("promptWithContextRecovery error = %v, want context overflow", err)
	190	+	}
	191	+	client.mu.Lock()
	192	+	calls := client.calls
	193	+	requests := append([]provider.Request(nil), client.requests...)
	194	+	client.mu.Unlock()
	195	+	if len(requests) != 1 \|\| workerRequestUserTextCount(requests[0], "finish the task") != 1 {
	196	+	t.Fatalf("initial request does not retain the prompt: %#v", requests)
	197	+	}
	198	+	if len(agent.Messages()) != 1 \|\| workerRequestMessageTextCount(agent.Messages(), "finish the task") != 1 {
	199	+	t.Fatalf("single prompt was not retained: %#v", agent.Messages())
	200	+	}
	201	+	if calls != 1 {
	202	+	t.Fatalf("provider calls = %d, want 1 without compaction", calls)
	203	+	}
	204	+	}
	205	+
	206	+	func TestPromptWithContextRecoveryRetainsPromptWhenPersistenceFails(t *testing.T) {
	207	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
	208	+	history := []provider.Message{{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "prior context"}}}}
	209	+	session, err := core.NewSession(t.TempDir(), "cwd", "provider", "model", "test")
	210	+	if err != nil {
	211	+	t.Fatalf("create session: %v", err)
	212	+	}
	213	+	if err := session.AppendMessage(history[0]); err != nil {
	214	+	t.Fatalf("append history: %v", err)
	215	+	}
	216	+	agent := core.NewAgent(client, "test-model", "", nil)
	217	+	agent.SetMessages(history)
	218	+
	219	+	outputStart, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, func([]provider.Message) error {
	220	+	return errors.New("persist failed")
	221	+	})
	222	+	if err == nil \|\| !strings.Contains(err.Error(), "persist compacted transcript") {
	223	+	t.Fatalf("promptWithContextRecovery error = %v, want persistence failure", err)
	224	+	}
	225	+	if got := workerRequestMessageTextCount(agent.Messages(), "prior context"); got != 1 \|\| workerRequestMessageTextCount(agent.Messages(), "finish the task") != 1 {
	226	+	t.Fatalf("agent transcript lost the pending task after persistence failure: %#v", agent.Messages())
	227	+	}
	228	+	WriteNewTranscript(agent, session, outputStart)
	229	+	if err := session.Close(); err != nil {
	230	+	t.Fatalf("close session: %v", err)
	231	+	}
	232	+	reopened, messages, err := core.OpenSession(session.Path)
	233	+	if err != nil {
	234	+	t.Fatalf("reopen session: %v", err)
	235	+	}
	236	+	t.Cleanup(func() {
	237	+	if err := reopened.Close(); err != nil {
	238	+	t.Errorf("close reopened session: %v", err)
	239	+	}
	240	+	})
	241	+	if got := workerRequestMessageTextCount(messages, "finish the task"); got != 1 {
	242	+	t.Fatalf("persisted prompt count = %d, want 1: %#v", got, messages)
	243	+	}
	244	+	client.mu.Lock()
	245	+	calls := client.calls
	246	+	client.mu.Unlock()
	247	+	if calls != 2 {
	248	+	t.Fatalf("provider calls = %d, want initial prompt and compaction only", calls)
	249	+	}
	250	+	}
	251	+
	252	+	func TestPromptWithContextRecoveryPersistsCompaction(t *testing.T) {
	253	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
	254	+	history := []provider.Message{
	255	+	{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "one"}}},
	256	+	{Role: provider.RoleAssistant, Content: []provider.Content{provider.TextBlock{Text: "two"}}},
	257	+	{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "three"}}},
	258	+	{Role: provider.RoleAssistant, Content: []provider.Content{provider.TextBlock{Text: "four"}}},
	259	+	}
	260	+	session, err := core.NewSession(t.TempDir(), "cwd", "provider", "model", "test")
	261	+	if err != nil {
	262	+	t.Fatalf("create session: %v", err)
	263	+	}
	264	+	for _, message := range history {
	265	+	if err := session.AppendMessage(message); err != nil {
	266	+	t.Fatalf("append history: %v", err)
	267	+	}
	268	+	}
	269	+
	270	+	agent := core.NewAgent(client, "test-model", "", nil)
	271	+	agent.SetMessages(history)
	272	+	outputStart, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, session.AppendCompaction)
	273	+	if err != nil {
	274	+	t.Fatalf("promptWithContextRecovery returned %v", err)
	275	+	}
	276	+	WriteNewTranscript(agent, session, outputStart)
	277	+	if err := session.Close(); err != nil {
	278	+	t.Fatalf("close session: %v", err)
	279	+	}
	280	+
	281	+	records, err := os.ReadFile(session.Path)
	282	+	if err != nil {
	283	+	t.Fatalf("read session: %v", err)
	284	+	}
	285	+	compactions := 0
	286	+	for _, record := range bytes.Split(bytes.TrimSpace(records), []byte("\n")) {
	287	+	var entry struct {
	288	+	Type string `json:"type"`
	289	+	}
	290	+	if err := json.Unmarshal(record, &entry); err != nil {
	291	+	t.Fatalf("decode session record: %v", err)
	292	+	}
	293	+	if entry.Type == "compaction" {
	294	+	compactions++
	295	+	}
	296	+	}
	297	+	if compactions != 1 {
	298	+	t.Fatalf("compaction records = %d, want 1", compactions)
	299	+	}
	300	+
	301	+	reopened, messages, err := core.OpenSession(session.Path)
	302	+	if err != nil {
	303	+	t.Fatalf("reopen session: %v", err)
	304	+	}
	305	+	t.Cleanup(func() {
	306	+	if err := reopened.Close(); err != nil {
	307	+	t.Errorf("close reopened session: %v", err)
	308	+	}
	309	+	})
	310	+	if got := workerRequestMessageTextCount(messages, "finish the task"); got != 1 {
	311	+	t.Fatalf("persisted prompt count = %d, want 1: %#v", got, messages)
	312	+	}
	313	+	if got := finalAssistantText(messages); got != "two\nfour\nrecovered" {
	314	+	t.Fatalf("persisted assistant text = %q, want prior tail plus recovered result", got)
	315	+	}
	316	+	}
	317	+
	318	+	func workerRequestMessageTextCount(messages []provider.Message, want string) int {
	319	+	count := 0
	320	+	for _, message := range messages {
	321	+	for _, block := range message.Content {
	322	+	if text, ok := block.(provider.TextBlock); ok && text.Text == want {
	323	+	count++
	324	+	}
	325	+	}
	326	+	}
	327	+	return count
	328	+	}
	329	+
	330	+	func workerRequestContainsText(req provider.Request, want string) bool {
	331	+	for _, message := range req.Messages {
	332	+	for _, block := range message.Content {
	333	+	if text, ok := block.(provider.TextBlock); ok && strings.Contains(text.Text, want) {
	334	+	return true
	335	+	}
	336	+	}
	337	+	}
	338	+	return false
	339	+	}
	340	+
	341	+	func workerRequestUserTextCount(req provider.Request, want string) int {
	342	+	count := 0
	343	+	for _, message := range req.Messages {
	344	+	if message.Role != provider.RoleUser {
	345	+	continue
	346	+	}
	347	+	for _, block := range message.Content {
	348	+	if text, ok := block.(provider.TextBlock); ok && text.Text == want {
	349	+	count++
	350	+	}
	351	+	}
	352	+	}
	353	+	return count
	354	+	}
	355	+
	356	+	func TestResultErrorPayloadSanitizesContextOverflow(t *testing.T) {
	357	+	payload := resultErrorPayload(errors.New("provider error: input exceeds the context window; echoed task text"))
	358	+	if payload["code"] != "context_limit" {
	359	+	t.Fatalf("error code = %q, want context_limit", payload["code"])
	360	+	}
	361	+	if payload["message"] != subagentContextLimitMessage {
	362	+	t.Fatalf("error message = %q, want %q", payload["message"], subagentContextLimitMessage)
	363	+	}
	364	+	}
	365	+
	366	+	func TestSubagentEventDataSanitizesContextOverflow(t *testing.T) {
	367	+	payload := subagentEventData(core.EvTurnEnd{Err: errors.New("provider error: input exceeds the context window; echoed task text")})
	368	+	if payload["error"] != subagentContextLimitMessage {
	369	+	t.Fatalf("event error = %q, want %q", payload["error"], subagentContextLimitMessage)
	370	+	}
	371	+	}
	372	+
33	373		// TestSupervisorEmitterMirrorDormantUntilStdoutBreaks regresses the
34	374		// "everything is doubled after reopening a subagent agent" bug.
35	375		//


@@ -2,14 +2,19 @@ package agent
2		2
3	import (	3		import (
4	"bytes"	4		"bytes"
		5	+	"context"
5	"encoding/json"	6		"encoding/json"
		7	+	"errors"
6	"io"	8		"io"
7	"os"	9		"os"
8	"path/filepath"	10		"path/filepath"
9	"strings"	11		"strings"
		12	+	"sync"
10	"testing"	13		"testing"
11		14
12	"github.com/bnema/zut/packages/agent/subagents"	15		"github.com/bnema/zut/packages/agent/subagents"
		16	+	"github.com/bnema/zut/packages/core"
		17	+	"github.com/bnema/zut/packages/provider"
13	)	18		)
14		19
15	// TestWorkerOutputLimitsUseSupervisorPolicy verifies that the child reads	20		// TestWorkerOutputLimitsUseSupervisorPolicy verifies that the child reads

@@ -30,6 +35,341 @@ func TestWorkerOutputLimitsUseSupervisorPolicy(t *testing.T) {
30	}	35		}
31	}	36		}
32		37
		38	+	type subagentContextRecoveryClient struct {
		39	+	mu sync.Mutex
		40	+	calls int
		41	+	requests []provider.Request
		42	+	retried chan provider.Request
		43	+	compactionErr error
		44	+	retryOverflow bool
		45	+	}
		46	+
		47	+	func (c *subagentContextRecoveryClient) Name() string { return "subagent-context-recovery-test" }
		48	+
		49	+	func (c *subagentContextRecoveryClient) Stream(_ context.Context, req provider.Request) (<-chan provider.Event, error) {
		50	+	c.mu.Lock()
		51	+	c.calls++
		52	+	call := c.calls
		53	+	c.requests = append(c.requests, req)
		54	+	c.mu.Unlock()
		55	+
		56	+	events := make(chan provider.Event, 2)
		57	+	go func() {
		58	+	defer close(events)
		59	+	switch call {
		60	+	case 1:
		61	+	events <- provider.EventDone{Stop: provider.StopError, Err: errors.New("provider error: input exceeds the context window")}
		62	+	case 2:
		63	+	if c.compactionErr != nil {
		64	+	events <- provider.EventDone{Stop: provider.StopError, Err: c.compactionErr}
		65	+	return
		66	+	}
		67	+	events <- provider.EventTextDelta{Delta: "summary"}
		68	+	events <- provider.EventDone{Stop: provider.StopEnd}
		69	+	default:
		70	+	c.retried <- req
		71	+	if c.retryOverflow {
		72	+	events <- provider.EventDone{Stop: provider.StopError, Err: errors.New("context window exceeded after compaction")}
		73	+	return
		74	+	}
		75	+	events <- provider.EventDone{Stop: provider.StopEnd, Message: provider.Message{
		76	+	Role: provider.RoleAssistant,
		77	+	Content: []provider.Content{provider.TextBlock{Text: "recovered"}},
		78	+	}}
		79	+	}
		80	+	}()
		81	+	return events, nil
		82	+	}
		83	+
		84	+	func TestPromptWithContextRecoveryCompactsAndContinues(t *testing.T) {
		85	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
		86	+	agent := core.NewAgent(client, "test-model", "", nil)
		87	+	agent.SetMessages([]provider.Message{
		88	+	{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "one"}}},
		89	+	{Role: provider.RoleAssistant, Content: []provider.Content{provider.TextBlock{Text: "two"}}},
		90	+	{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "three"}}},
		91	+	{Role: provider.RoleAssistant, Content: []provider.Content{provider.TextBlock{Text: "four"}}},
		92	+	})
		93	+
		94	+	outputStart, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, nil)
		95	+	if err != nil {
		96	+	t.Fatalf("promptWithContextRecovery returned %v", err)
		97	+	}
		98	+	if got := finalAssistantText(agent.Messages()[outputStart:]); got != "recovered" {
		99	+	t.Fatalf("final assistant text = %q, want recovered", got)
		100	+	}
		101	+
		102	+	request := <-client.retried
		103	+	if got := workerRequestUserTextCount(request, "finish the task"); got != 1 {
		104	+	t.Fatalf("retried request contains prompt %d times, want 1: %#v", got, request.Messages)
		105	+	}
		106	+	client.mu.Lock()
		107	+	calls := client.calls
		108	+	requests := append([]provider.Request(nil), client.requests...)
		109	+	client.mu.Unlock()
		110	+	if calls != 3 \|\| len(requests) != 3 {
		111	+	t.Fatalf("provider calls/requests = %d/%d, want 3/3", calls, len(requests))
		112	+	}
		113	+	if !workerRequestContainsText(requests[1], "<conversation>") \|\| !workerRequestContainsText(requests[1], "one") {
		114	+	t.Fatalf("compaction request does not include the older transcript: %#v", requests[1].Messages)
		115	+	}
		116	+	}
		117	+
		118	+	func TestPromptWithContextRecoveryStopsAfterOneRetry(t *testing.T) {
		119	+	client := &subagentContextRecoveryClient{
		120	+	retried: make(chan provider.Request, 1),
		121	+	retryOverflow: true,
		122	+	}
		123	+	agent := core.NewAgent(client, "test-model", "", nil)
		124	+	agent.SetMessages([]provider.Message{{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "prior context"}}}})
		125	+
		126	+	_, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, nil)
		127	+	if !provider.IsContextOverflowError(err) {
		128	+	t.Fatalf("promptWithContextRecovery error = %v, want context overflow", err)
		129	+	}
		130	+	<-client.retried
		131	+	client.mu.Lock()
		132	+	calls := client.calls
		133	+	client.mu.Unlock()
		134	+	if calls != 3 {
		135	+	t.Fatalf("provider calls = %d, want one initial prompt, compaction, and one continuation", calls)
		136	+	}
		137	+	}
		138	+
		139	+	func TestPromptWithContextRecoveryDoesNotCompactAfterCancellation(t *testing.T) {
		140	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
		141	+	agent := core.NewAgent(client, "test-model", "", nil)
		142	+	agent.SetMessages([]provider.Message{{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "prior context"}}}})
		143	+	ctx, cancel := context.WithCancel(context.Background())
		144	+	defer cancel()
		145	+
		146	+	_, err := promptWithContextRecovery(ctx, agent, "finish the task", func(event core.AgentEvent) {
		147	+	if turnEnd, ok := event.(core.EvTurnEnd); ok && provider.IsContextOverflowError(turnEnd.Err) {
		148	+	cancel()
		149	+	}
		150	+	}, nil)
		151	+	if !provider.IsContextOverflowError(err) {
		152	+	t.Fatalf("promptWithContextRecovery error = %v, want context overflow", err)
		153	+	}
		154	+	if err := ctx.Err(); !errors.Is(err, context.Canceled) {
		155	+	t.Fatalf("context error = %v, want %v", err, context.Canceled)
		156	+	}
		157	+	client.mu.Lock()
		158	+	calls := client.calls
		159	+	client.mu.Unlock()
		160	+	if calls != 1 {
		161	+	t.Fatalf("provider calls = %d, want only the initial prompt after cancellation", calls)
		162	+	}
		163	+	}
		164	+
		165	+	func TestPromptWithContextRecoveryPropagatesCompactionFailure(t *testing.T) {
		166	+	client := &subagentContextRecoveryClient{
		167	+	retried: make(chan provider.Request, 1),
		168	+	compactionErr: errors.New("compaction provider unavailable"),
		169	+	}
		170	+	agent := core.NewAgent(client, "test-model", "", nil)
		171	+	agent.SetMessages([]provider.Message{{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "prior context"}}}})
		172	+
		173	+	_, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, nil)
		174	+	if err == nil \|\| !strings.Contains(err.Error(), "compact transcript after initial overflow") {
		175	+	t.Fatalf("promptWithContextRecovery error = %v, want compaction failure", err)
		176	+	}
		177	+	payload := resultErrorPayload(err)
		178	+	if payload["code"] != "turn_failed" {
		179	+	t.Fatalf("result error payload = %#v, want turn_failed", payload)
		180	+	}
		181	+	}
		182	+
		183	+	func TestPromptWithContextRecoveryKeepsSinglePromptIntact(t *testing.T) {
		184	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
		185	+	agent := core.NewAgent(client, "test-model", "", nil)
		186	+
		187	+	_, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, nil)
		188	+	if !provider.IsContextOverflowError(err) {
		189	+	t.Fatalf("promptWithContextRecovery error = %v, want context overflow", err)
		190	+	}
		191	+	client.mu.Lock()
		192	+	calls := client.calls
		193	+	requests := append([]provider.Request(nil), client.requests...)
		194	+	client.mu.Unlock()
		195	+	if len(requests) != 1 \|\| workerRequestUserTextCount(requests[0], "finish the task") != 1 {
		196	+	t.Fatalf("initial request does not retain the prompt: %#v", requests)
		197	+	}
		198	+	if len(agent.Messages()) != 1 \|\| workerRequestMessageTextCount(agent.Messages(), "finish the task") != 1 {
		199	+	t.Fatalf("single prompt was not retained: %#v", agent.Messages())
		200	+	}
		201	+	if calls != 1 {
		202	+	t.Fatalf("provider calls = %d, want 1 without compaction", calls)
		203	+	}
		204	+	}
		205	+
		206	+	func TestPromptWithContextRecoveryRetainsPromptWhenPersistenceFails(t *testing.T) {
		207	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
		208	+	history := []provider.Message{{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "prior context"}}}}
		209	+	session, err := core.NewSession(t.TempDir(), "cwd", "provider", "model", "test")
		210	+	if err != nil {
		211	+	t.Fatalf("create session: %v", err)
		212	+	}
		213	+	if err := session.AppendMessage(history[0]); err != nil {
		214	+	t.Fatalf("append history: %v", err)
		215	+	}
		216	+	agent := core.NewAgent(client, "test-model", "", nil)
		217	+	agent.SetMessages(history)
		218	+
		219	+	outputStart, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, func([]provider.Message) error {
		220	+	return errors.New("persist failed")
		221	+	})
		222	+	if err == nil \|\| !strings.Contains(err.Error(), "persist compacted transcript") {
		223	+	t.Fatalf("promptWithContextRecovery error = %v, want persistence failure", err)
		224	+	}
		225	+	if got := workerRequestMessageTextCount(agent.Messages(), "prior context"); got != 1 \|\| workerRequestMessageTextCount(agent.Messages(), "finish the task") != 1 {
		226	+	t.Fatalf("agent transcript lost the pending task after persistence failure: %#v", agent.Messages())
		227	+	}
		228	+	WriteNewTranscript(agent, session, outputStart)
		229	+	if err := session.Close(); err != nil {
		230	+	t.Fatalf("close session: %v", err)
		231	+	}
		232	+	reopened, messages, err := core.OpenSession(session.Path)
		233	+	if err != nil {
		234	+	t.Fatalf("reopen session: %v", err)
		235	+	}
		236	+	t.Cleanup(func() {
		237	+	if err := reopened.Close(); err != nil {
		238	+	t.Errorf("close reopened session: %v", err)
		239	+	}
		240	+	})
		241	+	if got := workerRequestMessageTextCount(messages, "finish the task"); got != 1 {
		242	+	t.Fatalf("persisted prompt count = %d, want 1: %#v", got, messages)
		243	+	}
		244	+	client.mu.Lock()
		245	+	calls := client.calls
		246	+	client.mu.Unlock()
		247	+	if calls != 2 {
		248	+	t.Fatalf("provider calls = %d, want initial prompt and compaction only", calls)
		249	+	}
		250	+	}
		251	+
		252	+	func TestPromptWithContextRecoveryPersistsCompaction(t *testing.T) {
		253	+	client := &subagentContextRecoveryClient{retried: make(chan provider.Request, 1)}
		254	+	history := []provider.Message{
		255	+	{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "one"}}},
		256	+	{Role: provider.RoleAssistant, Content: []provider.Content{provider.TextBlock{Text: "two"}}},
		257	+	{Role: provider.RoleUser, Content: []provider.Content{provider.TextBlock{Text: "three"}}},
		258	+	{Role: provider.RoleAssistant, Content: []provider.Content{provider.TextBlock{Text: "four"}}},
		259	+	}
		260	+	session, err := core.NewSession(t.TempDir(), "cwd", "provider", "model", "test")
		261	+	if err != nil {
		262	+	t.Fatalf("create session: %v", err)
		263	+	}
		264	+	for _, message := range history {
		265	+	if err := session.AppendMessage(message); err != nil {
		266	+	t.Fatalf("append history: %v", err)
		267	+	}
		268	+	}
		269	+
		270	+	agent := core.NewAgent(client, "test-model", "", nil)
		271	+	agent.SetMessages(history)
		272	+	outputStart, err := promptWithContextRecovery(context.Background(), agent, "finish the task", nil, session.AppendCompaction)
		273	+	if err != nil {
		274	+	t.Fatalf("promptWithContextRecovery returned %v", err)
		275	+	}
		276	+	WriteNewTranscript(agent, session, outputStart)
		277	+	if err := session.Close(); err != nil {
		278	+	t.Fatalf("close session: %v", err)
		279	+	}
		280	+
		281	+	records, err := os.ReadFile(session.Path)
		282	+	if err != nil {
		283	+	t.Fatalf("read session: %v", err)
		284	+	}
		285	+	compactions := 0
		286	+	for _, record := range bytes.Split(bytes.TrimSpace(records), []byte("\n")) {
		287	+	var entry struct {
		288	+	Type string `json:"type"`
		289	+	}
		290	+	if err := json.Unmarshal(record, &entry); err != nil {
		291	+	t.Fatalf("decode session record: %v", err)
		292	+	}
		293	+	if entry.Type == "compaction" {
		294	+	compactions++
		295	+	}
		296	+	}
		297	+	if compactions != 1 {
		298	+	t.Fatalf("compaction records = %d, want 1", compactions)
		299	+	}
		300	+
		301	+	reopened, messages, err := core.OpenSession(session.Path)
		302	+	if err != nil {
		303	+	t.Fatalf("reopen session: %v", err)
		304	+	}
		305	+	t.Cleanup(func() {
		306	+	if err := reopened.Close(); err != nil {
		307	+	t.Errorf("close reopened session: %v", err)
		308	+	}
		309	+	})
		310	+	if got := workerRequestMessageTextCount(messages, "finish the task"); got != 1 {
		311	+	t.Fatalf("persisted prompt count = %d, want 1: %#v", got, messages)
		312	+	}
		313	+	if got := finalAssistantText(messages); got != "two\nfour\nrecovered" {
		314	+	t.Fatalf("persisted assistant text = %q, want prior tail plus recovered result", got)
		315	+	}
		316	+	}
		317	+
		318	+	func workerRequestMessageTextCount(messages []provider.Message, want string) int {
		319	+	count := 0
		320	+	for _, message := range messages {
		321	+	for _, block := range message.Content {
		322	+	if text, ok := block.(provider.TextBlock); ok && text.Text == want {
		323	+	count++
		324	+	}
		325	+	}
		326	+	}
		327	+	return count
		328	+	}
		329	+
		330	+	func workerRequestContainsText(req provider.Request, want string) bool {
		331	+	for _, message := range req.Messages {
		332	+	for _, block := range message.Content {
		333	+	if text, ok := block.(provider.TextBlock); ok && strings.Contains(text.Text, want) {
		334	+	return true
		335	+	}
		336	+	}
		337	+	}
		338	+	return false
		339	+	}
		340	+
		341	+	func workerRequestUserTextCount(req provider.Request, want string) int {
		342	+	count := 0
		343	+	for _, message := range req.Messages {
		344	+	if message.Role != provider.RoleUser {
		345	+	continue
		346	+	}
		347	+	for _, block := range message.Content {
		348	+	if text, ok := block.(provider.TextBlock); ok && text.Text == want {
		349	+	count++
		350	+	}
		351	+	}
		352	+	}
		353	+	return count
		354	+	}
		355	+
		356	+	func TestResultErrorPayloadSanitizesContextOverflow(t *testing.T) {
		357	+	payload := resultErrorPayload(errors.New("provider error: input exceeds the context window; echoed task text"))
		358	+	if payload["code"] != "context_limit" {
		359	+	t.Fatalf("error code = %q, want context_limit", payload["code"])
		360	+	}
		361	+	if payload["message"] != subagentContextLimitMessage {
		362	+	t.Fatalf("error message = %q, want %q", payload["message"], subagentContextLimitMessage)
		363	+	}
		364	+	}
		365	+
		366	+	func TestSubagentEventDataSanitizesContextOverflow(t *testing.T) {
		367	+	payload := subagentEventData(core.EvTurnEnd{Err: errors.New("provider error: input exceeds the context window; echoed task text")})
		368	+	if payload["error"] != subagentContextLimitMessage {
		369	+	t.Fatalf("event error = %q, want %q", payload["error"], subagentContextLimitMessage)
		370	+	}
		371	+	}
		372	+
33	// TestSupervisorEmitterMirrorDormantUntilStdoutBreaks regresses the	373		// TestSupervisorEmitterMirrorDormantUntilStdoutBreaks regresses the
34	// "everything is doubled after reopening a subagent agent" bug.	374		// "everything is doubled after reopening a subagent agent" bug.
35	//	375		//

A packages/provider/context_overflow.go +42 -0

@@ -0,0 +1,42 @@
	1	+	package provider
	2	+
	3	+	import "strings"
	4	+
	5	+	// IsContextOverflowError reports whether err indicates that the provider
	6	+	// rejected a request because its payload or tokenized input exceeds the
	7	+	// serving model's context limit. Provider responses use different HTTP status
	8	+	// codes, error codes, and prose, so callers use this semantic classification
	9	+	// when deciding whether compaction is a safe recovery attempt.
	10	+	func IsContextOverflowError(err error) bool {
	11	+	if err == nil {
	12	+	return false
	13	+	}
	14	+	msg := strings.ToLower(err.Error())
	15	+	return hasHTTPStatus(msg, "413") \|\|
	16	+	strings.Contains(msg, "payload too large") \|\|
	17	+	strings.Contains(msg, "request entity too large") \|\|
	18	+	strings.Contains(msg, "input exceeds the context window") \|\|
	19	+	strings.Contains(msg, "context window exceeded") \|\|
	20	+	strings.Contains(msg, "maximum context length") \|\|
	21	+	strings.Contains(msg, "context_length_exceeded") \|\|
	22	+	(strings.Contains(msg, "input") && strings.Contains(msg, "exceeds the maximum number of tokens"))
	23	+	}
	24	+
	25	+	func hasHTTPStatus(message, code string) bool {
	26	+	fields := strings.Fields(message)
	27	+	for i, field := range fields {
	28	+	if strings.Trim(field, "():,;[]{}") != code {
	29	+	continue
	30	+	}
	31	+	if i == 0 {
	32	+	return true
	33	+	}
	34	+	for offset := 1; offset <= 2 && i-offset >= 0; offset++ {
	35	+	prefix := strings.Trim(fields[i-offset], "():,;[]{}")
	36	+	if prefix == "http" \|\| prefix == "status" \|\| prefix == "response" {
	37	+	return true
	38	+	}
	39	+	}
	40	+	}
	41	+	return false
	42	+	}

@@ -0,0 +1,42 @@
	1	+	package provider
	2	+
	3	+	import "strings"
	4	+
	5	+	// IsContextOverflowError reports whether err indicates that the provider
	6	+	// rejected a request because its payload or tokenized input exceeds the
	7	+	// serving model's context limit. Provider responses use different HTTP status
	8	+	// codes, error codes, and prose, so callers use this semantic classification
	9	+	// when deciding whether compaction is a safe recovery attempt.
	10	+	func IsContextOverflowError(err error) bool {
	11	+	if err == nil {
	12	+	return false
	13	+	}
	14	+	msg := strings.ToLower(err.Error())
	15	+	return hasHTTPStatus(msg, "413") \|\|
	16	+	strings.Contains(msg, "payload too large") \|\|
	17	+	strings.Contains(msg, "request entity too large") \|\|
	18	+	strings.Contains(msg, "input exceeds the context window") \|\|
	19	+	strings.Contains(msg, "context window exceeded") \|\|
	20	+	strings.Contains(msg, "maximum context length") \|\|
	21	+	strings.Contains(msg, "context_length_exceeded") \|\|
	22	+	(strings.Contains(msg, "input") && strings.Contains(msg, "exceeds the maximum number of tokens"))
	23	+	}
	24	+
	25	+	func hasHTTPStatus(message, code string) bool {
	26	+	fields := strings.Fields(message)
	27	+	for i, field := range fields {
	28	+	if strings.Trim(field, "():,;[]{}") != code {
	29	+	continue
	30	+	}
	31	+	if i == 0 {
	32	+	return true
	33	+	}
	34	+	for offset := 1; offset <= 2 && i-offset >= 0; offset++ {
	35	+	prefix := strings.Trim(fields[i-offset], "():,;[]{}")
	36	+	if prefix == "http" \|\| prefix == "status" \|\| prefix == "response" {
	37	+	return true
	38	+	}
	39	+	}
	40	+	}
	41	+	return false
	42	+	}

A packages/provider/context_overflow_test.go +37 -0

@@ -0,0 +1,37 @@
	1	+	package provider
	2	+
	3	+	import (
	4	+	"errors"
	5	+	"testing"
	6	+	)
	7	+
	8	+	func TestIsContextOverflowError(t *testing.T) {
	9	+	tests := []struct {
	10	+	name string
	11	+	err error
	12	+	want bool
	13	+	}{
	14	+	{name: "nil error", err: nil, want: false},
	15	+	{name: "http 413", err: errors.New("provider http 413: request rejected"), want: true},
	16	+	{name: "response 413", err: errors.New("provider response 413: request rejected"), want: true},
	17	+	{name: "HTTP status code 413", err: errors.New("provider request failed: HTTP status code: 413"), want: true},
	18	+	{name: "payload too large", err: errors.New("proxy rejected request: Payload Too Large"), want: true},
	19	+	{name: "request entity too large", err: errors.New("gateway: Request Entity Too Large"), want: true},
	20	+	{name: "numeric value is not HTTP 413", err: errors.New("provider http 400: max_tokens cannot exceed 41344"), want: false},
	21	+	{name: "unqualified numeric value is not HTTP 413", err: errors.New("max_tokens cannot exceed 413"), want: false},
	22	+	{name: "context error code", err: errors.New("context_length_exceeded"), want: true},
	23	+	{name: "maximum context length", err: errors.New("This model's maximum context length is 128000 tokens"), want: true},
	24	+	{name: "context window exceeded", err: errors.New("context window exceeded"), want: true},
	25	+	{name: "maximum input token count", err: errors.New("input token count exceeds the maximum number of tokens allowed"), want: true},
	26	+	{name: "maximum output token count", err: errors.New("max_tokens exceeds the maximum number of tokens allowed"), want: false},
	27	+	{name: "unrelated error", err: errors.New("rate limit exceeded"), want: false},
	28	+	}
	29	+
	30	+	for _, tt := range tests {
	31	+	t.Run(tt.name, func(t *testing.T) {
	32	+	if got := IsContextOverflowError(tt.err); got != tt.want {
	33	+	t.Fatalf("IsContextOverflowError(%q) = %t, want %t", tt.err, got, tt.want)
	34	+	}
	35	+	})
	36	+	}
	37	+	}

@@ -0,0 +1,37 @@
	1	+	package provider
	2	+
	3	+	import (
	4	+	"errors"
	5	+	"testing"
	6	+	)
	7	+
	8	+	func TestIsContextOverflowError(t *testing.T) {
	9	+	tests := []struct {
	10	+	name string
	11	+	err error
	12	+	want bool
	13	+	}{
	14	+	{name: "nil error", err: nil, want: false},
	15	+	{name: "http 413", err: errors.New("provider http 413: request rejected"), want: true},
	16	+	{name: "response 413", err: errors.New("provider response 413: request rejected"), want: true},
	17	+	{name: "HTTP status code 413", err: errors.New("provider request failed: HTTP status code: 413"), want: true},
	18	+	{name: "payload too large", err: errors.New("proxy rejected request: Payload Too Large"), want: true},
	19	+	{name: "request entity too large", err: errors.New("gateway: Request Entity Too Large"), want: true},
	20	+	{name: "numeric value is not HTTP 413", err: errors.New("provider http 400: max_tokens cannot exceed 41344"), want: false},
	21	+	{name: "unqualified numeric value is not HTTP 413", err: errors.New("max_tokens cannot exceed 413"), want: false},
	22	+	{name: "context error code", err: errors.New("context_length_exceeded"), want: true},
	23	+	{name: "maximum context length", err: errors.New("This model's maximum context length is 128000 tokens"), want: true},
	24	+	{name: "context window exceeded", err: errors.New("context window exceeded"), want: true},
	25	+	{name: "maximum input token count", err: errors.New("input token count exceeds the maximum number of tokens allowed"), want: true},
	26	+	{name: "maximum output token count", err: errors.New("max_tokens exceeds the maximum number of tokens allowed"), want: false},
	27	+	{name: "unrelated error", err: errors.New("rate limit exceeded"), want: false},
	28	+	}
	29	+
	30	+	for _, tt := range tests {
	31	+	t.Run(tt.name, func(t *testing.T) {
	32	+	if got := IsContextOverflowError(tt.err); got != tt.want {
	33	+	t.Fatalf("IsContextOverflowError(%q) = %t, want %t", tt.err, got, tt.want)
	34	+	}
	35	+	})
	36	+	}
	37	+	}