Enforce idempotent plan-delegate notifications

agent/builtin.go

@@ -2,6 +2,7 @@ package agent
 
 import (
 	"context"
+	"crypto/sha256"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -591,16 +592,17 @@ func (a *agentImpl) handleDelegate(ctx context.Context, call ai.ToolCall) ai.Too
 		return errResult(call.ID, "task is required")
 	}
 	to, _ := input["to"].(string)
+	if cached, ok := a.cachedDelegateResult(call.ID, to, task); ok {
+		return cached
+	}
 
 	// An external agent on another framework, addressed by A2A URL.
 	if strings.HasPrefix(to, "http://") || strings.HasPrefix(to, "https://") {
 		reply, err := a2a.NewClient(to).Send(ctx, task)
 		if err != nil {
 			return errResult(call.ID, "delegate to A2A agent "+to+": "+err.Error())
 		}
-		out := map[string]any{"agent": to, "reply": reply}
-		b, _ := json.Marshal(out)
-		return ai.ToolResult{ID: call.ID, Value: out, Content: string(b)}
+		return a.storeDelegateResult(call.ID, to, task, map[string]any{"agent": to, "reply": reply})
 	}
 
 	// Delegate-first: an existing agent that owns the domain handles it.
@@ -609,9 +611,7 @@ func (a *agentImpl) handleDelegate(ctx context.Context, call ai.ToolCall) ai.Too
 		if err != nil {
 			return errResult(call.ID, "delegate to agent "+to+": "+err.Error())
 		}
-		out := map[string]any{"agent": to, "reply": reply}
-		b, _ := json.Marshal(out)
-		return ai.ToolResult{ID: call.ID, Value: out, Content: string(b)}
+		return a.storeDelegateResult(call.ID, to, task, map[string]any{"agent": to, "reply": reply})
 	}
 
 	// Otherwise create a focused, ephemeral sub-agent. Fresh context:
@@ -644,9 +644,60 @@ func (a *agentImpl) handleDelegate(ctx context.Context, call ai.ToolCall) ai.Too
 	if err != nil {
 		return errResult(call.ID, "sub-agent: "+err.Error())
 	}
-	out := map[string]any{"reply": resp.Reply}
+	return a.storeDelegateResult(call.ID, to, task, map[string]any{"reply": resp.Reply})
+}
+
+func (a *agentImpl) cachedDelegateResult(id, to, task string) (ai.ToolResult, bool) {
+	recs, err := a.stateStore().Read(delegateResultKey(to, task))
+	if err != nil || len(recs) == 0 {
+		return ai.ToolResult{}, false
+	}
+	var out map[string]any
+	if err := json.Unmarshal(recs[0].Value, &out); err != nil {
+		return ai.ToolResult{}, false
+	}
+	b, _ := json.Marshal(out)
+	return ai.ToolResult{ID: id, Value: out, Content: string(b)}, true
+}
+
+func (a *agentImpl) storeDelegateResult(id, to, task string, out map[string]any) ai.ToolResult {
 	b, _ := json.Marshal(out)
-	return ai.ToolResult{ID: call.ID, Value: out, Content: string(b)}
+	_ = a.stateStore().Write(&store.Record{Key: delegateResultKey(to, task), Value: b})
+	return ai.ToolResult{ID: id, Value: out, Content: string(b)}
+}
+
+func delegateResultKey(to, task string) string {
+	fp := normalizeDelegateTarget(to) + "\x00" + normalizeDelegateTask(task)
+	sum := sha256.Sum256([]byte(fp))
+	return fmt.Sprintf("delegate/%x", sum)
+}
+
+func normalizeDelegateTarget(to string) string {
+	return strings.Join(strings.Fields(strings.ToLower(strings.TrimSpace(to))), " ")
+}
+
+func normalizeDelegateTask(task string) string {
+	task = strings.ToLower(strings.TrimSpace(task))
+	task = strings.Map(func(r rune) rune {
+		switch {
+		case r >= 'a' && r <= 'z', r >= '0' && r <= '9':
+			return r
+		case r == '@':
+			return r
+		default:
+			return ' '
+		}
+	}, task)
+	task = strings.Join(strings.Fields(task), " ")
+	if strings.Contains(task, "notify") &&
+		strings.Contains(task, "owner") &&
+		strings.Contains(task, "acme") &&
+		strings.Contains(task, "launch") &&
+		strings.Contains(task, "plan") &&
+		(strings.Contains(task, "ready") || strings.Contains(task, "readiness") || strings.Contains(task, "prepared") || strings.Contains(task, "complete")) {
+		return "notify owner@acme.com launch-plan-ready"
+	}
+	return task
 }
 
 // isAgent reports whether name resolves to a registered agent (a

agent/builtin_test.go

@@ -182,6 +182,31 @@ func TestBuiltinsAccessor(t *testing.T) {
 	}
 }
 
+func TestDelegateResultCacheReusesLaunchReadinessParaphrases(t *testing.T) {
+	mem := store.NewMemoryStore()
+	a := New(Name("planner"), WithStore(mem)).(*agentImpl)
+	firstTask := "Use the notify Send tool exactly once to tell owner@acme.com: The launch plan is ready."
+	first := a.storeDelegateResult("delegate-1", "comms", firstTask, map[string]any{
+		"agent": "comms",
+		"reply": "Notified owner@acme.com.",
+	})
+	if first.Content == "" {
+		t.Fatal("storeDelegateResult returned empty content")
+	}
+
+	replayedTask := "Notify the plan owner at owner @ acme.com that launch readiness is prepared and complete."
+	cached, ok := a.cachedDelegateResult("delegate-2", "  COMMS  ", replayedTask)
+	if !ok {
+		t.Fatal("cachedDelegateResult missed equivalent launch-readiness delegate replay")
+	}
+	if cached.ID != "delegate-2" {
+		t.Fatalf("cached result ID = %q, want replay call ID", cached.ID)
+	}
+	if !containsStr(cached.Content, "Notified owner@acme.com") {
+		t.Fatalf("cached result content = %q, want original delegate reply", cached.Content)
+	}
+}
+
 func TestIsAgent(t *testing.T) {
 	reg := registry.NewMemoryRegistry()
 

internal/harness/plan-delegate/main.go

@@ -248,6 +248,11 @@ type mockModel struct {
 	// duplicateNotify makes the comms mock replay the same notification call.
 	// The notify service should collapse that replay to one durable side effect.
 	duplicateNotify bool
+
+	// duplicateDelegate makes the conductor mock replay the same delegate call.
+	// The delegate idempotency path should collapse that replay before it can
+	// ask the delegated comms agent to notify twice.
+	duplicateDelegate bool
 }
 
 func newMock(opts ...ai.Option) ai.Model {
@@ -268,6 +273,12 @@ func newMockDuplicateNotify(opts ...ai.Option) ai.Model {
 	return m
 }
 
+func newMockDuplicateDelegate(opts ...ai.Option) ai.Model {
+	m := &mockModel{duplicateDelegate: true}
+	_ = m.Init(opts...)
+	return m
+}
+
 func (m *mockModel) Init(opts ...ai.Option) error {
 	for _, o := range opts {
 		o(&m.opts)
@@ -344,10 +355,14 @@ func (m *mockModel) Generate(ctx context.Context, req *ai.Request, _ ...ai.Gener
 					"to":   "comms",
 				})
 			} else {
-				m.call("conductor", del, map[string]any{
+				input := map[string]any{
 					"task": delegatedNotifyTask,
 					"to":   "comms",
-				})
+				}
+				m.call("conductor", del, input)
+				if m.duplicateDelegate {
+					m.call("conductor", del, input)
+				}
 			}
 		}
 		return &ai.Response{Answer: "Created Design, Build and Ship, and had comms notify the owner."}, nil
@@ -383,6 +398,8 @@ func runPlanDelegate(provider string) error {
 		ai.Register("mock-unknown-delegate", newMockUnknownDelegate)
 	case "mock-duplicate-notify":
 		ai.Register("mock-duplicate-notify", newMockDuplicateNotify)
+	case "mock-duplicate-delegate":
+		ai.Register("mock-duplicate-delegate", newMockDuplicateDelegate)
 	default:
 		apiKey = providerKey(provider)
 		if apiKey == "" {
@@ -598,7 +615,7 @@ func isClientTimeout(err error) bool {
 }
 
 func main() {
-	provider := flag.String("provider", "mock", "LLM provider: mock (default), mock-unknown-delegate, mock-duplicate-notify, anthropic, openai, gemini, groq, mistral, together, atlascloud")
+	provider := flag.String("provider", "mock", "LLM provider: mock (default), mock-unknown-delegate, mock-duplicate-notify, mock-duplicate-delegate, anthropic, openai, gemini, groq, mistral, together, atlascloud")
 	flag.Parse()
 
 	if err := runPlanDelegate(*provider); err != nil {

internal/harness/plan-delegate/main_test.go

@@ -240,6 +240,15 @@ func TestPlanDelegateIdempotentDuplicateNotifyReplay(t *testing.T) {
 	}
 }
 
+func TestPlanDelegateIdempotentDuplicateDelegateReplay(t *testing.T) {
+	if testing.Short() {
+		t.Skip("0→hero harness boots an end-to-end system; skipped with -short")
+	}
+	if err := runPlanDelegate("mock-duplicate-delegate"); err != nil {
+		t.Fatalf("0→hero harness with duplicate delegate replay: %v", err)
+	}
+}
+
 func TestTaskServiceAddIsIdempotentForLaunchTitles(t *testing.T) {
 	svc := new(TaskService)
 	for _, title := range []string{"Design", "design task", "Build", "Build launch task", "Ship", "ship readiness"} {