fix(prompt-gate): harden internal prompt dispatch

src/hooks/todo-continuation-enforcer/continuation-injection.test.ts

@@ -238,7 +238,7 @@ describe("injectContinuation", () => {
     expect(capturedBody?.variant).toBe("max")
   })
 
-  test("#given a peer-message hold survives an unrelated release #when todo continuation injects #then it skips and clears in-flight state", async () => {
+  test("#given a peer-message hold survives an unrelated release #when todo continuation injects #then it queues behind the peer message", async () => {
     // given
     const sessionID = "ses_todo_reserved_by_peer_message"
     let promptCalls = 0
@@ -286,6 +286,50 @@ describe("injectContinuation", () => {
     expect(peerMessageResult.status).toBe("dispatched")
     expect(promptCalls).toBe(1)
     expect(state.inFlight).toBe(false)
-    expect(state.lastInjectedAt).toBe(0)
+    expect(state.lastInjectedAt).toBeGreaterThan(0)
+  })
+
+  test("#given promptAsync may have accepted before EOF #when continuation injection observes the failure #then it records an optimistic injection", async () => {
+    // given
+    const state = {
+      inFlight: false,
+      lastInjectedAt: 0,
+      awaitingPostInjectionProgressCheck: false,
+      consecutiveFailures: 2,
+    }
+    let promptCalls = 0
+    const ctx = {
+      directory: "/tmp/test",
+      client: {
+        session: {
+          todo: async () => ({ data: [{ id: "1", content: "todo", status: "pending", priority: "high" }] }),
+          promptAsync: async () => {
+            promptCalls += 1
+            throw new Error("JSON Parse error: Unexpected EOF")
+          },
+        },
+      },
+    }
+    const sessionStateStore = {
+      getExistingState: () => state,
+    }
+
+    // when
+    await injectContinuation({
+      ctx: ctx as never,
+      sessionID: "ses_continuation_eof",
+      resolvedInfo: {
+        agent: "Sisyphus - Ultraworker",
+        model: { providerID: "anthropic", modelID: "claude-sonnet-4-20250514" },
+      },
+      sessionStateStore: sessionStateStore as never,
+    })
+
+    // then
+    expect(promptCalls).toBe(1)
+    expect(state.inFlight).toBe(false)
+    expect(state.awaitingPostInjectionProgressCheck).toBe(true)
+    expect(state.consecutiveFailures).toBe(0)
+    expect(state.lastInjectedAt).toBeGreaterThan(0)
   })
 })

src/hooks/todo-continuation-enforcer/continuation-injection.ts

@@ -7,6 +7,7 @@ import {
 } from "../../features/claude-code-session-state"
 import {
   createInternalAgentContinuationTextPart,
+  isAmbiguousPromptDispatchFailure,
   normalizeSDKResponse,
   resolveInheritedPromptTools,
 } from "../../shared"
@@ -22,7 +23,7 @@ import {
   normalizeAgentForPromptKey,
   stripAgentListSortPrefix,
 } from "../../shared/agent-display-names"
-import { dispatchInternalPrompt } from "../shared/prompt-async-gate"
+import { dispatchInternalPrompt, isInternalPromptDispatchAccepted } from "../shared/prompt-async-gate"
 
 import {
   CONTINUATION_PROMPT,
@@ -208,7 +209,7 @@ ${todoList}`
     if (promptResult.status === "failed") {
       throw promptResult.error
     }
-    if (promptResult.status !== "dispatched") {
+    if (!isInternalPromptDispatchAccepted(promptResult)) {
       log(`[${HOOK_NAME}] Injection skipped by promptAsync gate`, { sessionID, status: promptResult.status })
       if (injectionState) {
         injectionState.inFlight = false
@@ -216,7 +217,7 @@ ${todoList}`
       return
     }
 
-    log(`[${HOOK_NAME}] Injection successful`, { sessionID })
+    log(`[${HOOK_NAME}] Injection successful`, { sessionID, status: promptResult.status })
     if (injectionState) {
       injectionState.inFlight = false
       injectionState.lastInjectedAt = Date.now()
@@ -228,6 +229,11 @@ ${todoList}`
     if (injectionState) {
       injectionState.inFlight = false
       injectionState.lastInjectedAt = Date.now()
+      if (isAmbiguousPromptDispatchFailure(error)) {
+        injectionState.awaitingPostInjectionProgressCheck = true
+        injectionState.consecutiveFailures = 0
+        return
+      }
       injectionState.consecutiveFailures = (injectionState.consecutiveFailures ?? 0) + 1
 
       const errorObj = error instanceof Error