diff --git a/src/hooks/runtime-fallback/first-prompt-watchdog.test.ts b/src/hooks/runtime-fallback/first-prompt-watchdog.test.ts
index 98767bf65..84d62510d 100644
--- a/src/hooks/runtime-fallback/first-prompt-watchdog.test.ts
+++ b/src/hooks/runtime-fallback/first-prompt-watchdog.test.ts
@@ -149,6 +149,70 @@ describe("first-prompt-watchdog", () => {
     watchdog.dispose()
   })
 
+  it("#given session emits message.part.updated with sessionID under properties.part #when watchdog tracks #then the watchdog recognizes progress and resets the silence timer", async () => {
+    // given
+    const sessionID = "session-nested-part-progress"
+    subagentSessions.add(sessionID)
+    const deps = createDeps(PLUGIN_CONFIG_WITH_FALLBACK)
+    const calls: RecordedCalls = { abort: [], autoRetry: [] }
+    const helpers = createHelpers(calls, AGENT)
+    const watchdog = createFirstPromptWatchdog(deps, helpers, WATCHDOG_MS)
+
+    // when
+    watchdog.onUserMessage(sessionID, PRIMARY_MODEL, AGENT)
+    await wait(SAFE_WAIT_BEFORE_FIRE_MS)
+    observeEventForWatchdog(
+      {
+        type: "message.part.updated",
+        properties: {
+          part: {
+            id: "part-1",
+            messageID: "msg-1",
+            sessionID,
+            type: "text",
+            text: "still working",
+          },
+        },
+      },
+      watchdog,
+    )
+    await wait(SAFE_WAIT_AFTER_FIRE_MS)
+
+    // then
+    expect(calls.abort).toEqual([])
+    expect(calls.autoRetry).toEqual([])
+
+    watchdog.dispose()
+  })
+
+  it("#given session emits message.part.delta with field/delta but no part.type #when watchdog tracks #then the watchdog recognizes progress", async () => {
+    // given
+    const sessionID = "session-delta-progress"
+    subagentSessions.add(sessionID)
+    const deps = createDeps(PLUGIN_CONFIG_WITH_FALLBACK)
+    const calls: RecordedCalls = { abort: [], autoRetry: [] }
+    const helpers = createHelpers(calls, AGENT)
+    const watchdog = createFirstPromptWatchdog(deps, helpers, WATCHDOG_MS)
+
+    // when
+    watchdog.onUserMessage(sessionID, PRIMARY_MODEL, AGENT)
+    await wait(SAFE_WAIT_BEFORE_FIRE_MS)
+    observeEventForWatchdog(
+      {
+        type: "message.part.delta",
+        properties: { sessionID, field: "text", delta: "x" },
+      },
+      watchdog,
+    )
+    await wait(SAFE_WAIT_AFTER_FIRE_MS)
+
+    // then
+    expect(calls.abort).toEqual([])
+    expect(calls.autoRetry).toEqual([])
+
+    watchdog.dispose()
+  })
+
   it("#given the session is not a subagent #when a user message is observed #then the watchdog never arms and nothing fires", async () => {
     // given
     const sessionID = "session-not-a-subagent"
diff --git a/src/hooks/runtime-fallback/first-prompt-watchdog.ts b/src/hooks/runtime-fallback/first-prompt-watchdog.ts
index 1af473d40..7ee8f2265 100644
--- a/src/hooks/runtime-fallback/first-prompt-watchdog.ts
+++ b/src/hooks/runtime-fallback/first-prompt-watchdog.ts
@@ -3,6 +3,8 @@ import type { AutoRetryHelpers } from "./auto-retry"
 import { HOOK_NAME, DEFAULT_FIRST_PROMPT_WATCHDOG_MS } from "./constants"
 import { log } from "../../shared/logger"
 import { subagentSessions } from "../../features/claude-code-session-state"
+import { resolveMessageEventSessionID, resolveSessionEventID } from "../../shared/event-session-id"
+import { isRecord } from "../../shared/record-type-guard"
 import { createFallbackState } from "./fallback-state"
 import { getFallbackModelsForSession } from "./fallback-models"
 import { resolveFallbackBootstrapModel } from "./fallback-bootstrap-model"
@@ -43,25 +45,26 @@ export function observeEventForWatchdog(
   event: { type: string; properties?: unknown },
   watchdog: FirstPromptWatchdog,
 ): void {
-  const props = event.properties as Record<string, unknown> | undefined
+  const props = isRecord(event.properties) ? event.properties : undefined
   if (!props) return
 
   if (event.type === "message.part.updated" || event.type === "message.part.delta") {
-    const sessionID = props.sessionID as string | undefined
-    const part = props.part as Record<string, unknown> | undefined
-    const partType = typeof part?.type === "string"
-      ? part.type
-      : typeof props.type === "string" ? props.type : undefined
-    if (sessionID && partType) {
+    const sessionID = resolveMessageEventSessionID(props)
+    const part = isRecord(props.part) ? props.part : undefined
+    const hasPartType = typeof part?.type === "string"
+    const hasTopLevelType = typeof props.type === "string"
+    const hasTextDelta = props.field === "text" && typeof props.delta === "string"
+    const hasNonEmptySessionPart = typeof part?.sessionID === "string" && Object.keys(part).length > 0
+    if (sessionID && (hasPartType || hasTopLevelType || hasTextDelta || hasNonEmptySessionPart)) {
       watchdog.onAssistantProgress(sessionID)
     }
     return
   }
 
   if (event.type === "message.updated") {
-    const info = props.info as Record<string, unknown> | undefined
-    const sessionID = info?.sessionID as string | undefined
-    const role = info?.role as string | undefined
+    const info = isRecord(props.info) ? props.info : undefined
+    const sessionID = typeof info?.sessionID === "string" ? info.sessionID : undefined
+    const role = typeof info?.role === "string" ? info.role : undefined
     if (!sessionID || !role) return
 
     if (role === "user") {
@@ -74,10 +77,10 @@ export function observeEventForWatchdog(
     if (role === "assistant") {
       const hasError = info?.error !== undefined
       const hasFinish = info?.finish !== undefined
-      const eventParts = props.parts as Array<{ type?: string }> | undefined
-      const infoParts = info?.parts as Array<{ type?: string }> | undefined
+      const eventParts = Array.isArray(props.parts) ? props.parts : undefined
+      const infoParts = Array.isArray(info?.parts) ? info.parts : undefined
       const parts = eventParts ?? infoParts ?? []
-      const hasAnyPart = parts.some((part) => typeof part?.type === "string")
+      const hasAnyPart = parts.some((part) => isRecord(part) && typeof part.type === "string")
       if (hasError || hasFinish || hasAnyPart) {
         watchdog.onAssistantProgress(sessionID)
       }
@@ -86,9 +89,7 @@ export function observeEventForWatchdog(
   }
 
   if (TERMINAL_EVENT_TYPES.has(event.type)) {
-    const sessionID =
-      (props.sessionID as string | undefined) ??
-      ((props.info as Record<string, unknown> | undefined)?.id as string | undefined)
+    const sessionID = resolveSessionEventID(props)
     if (sessionID) watchdog.onSessionTerminal(sessionID)
   }
 }
diff --git a/src/hooks/shared/prompt-async-gate.test.ts b/src/hooks/shared/prompt-async-gate.test.ts
index d3e526b56..8b0c79705 100644
--- a/src/hooks/shared/prompt-async-gate.test.ts
+++ b/src/hooks/shared/prompt-async-gate.test.ts
@@ -751,6 +751,86 @@ describe("dispatchInternalPrompt shared gate behavior", () => {
     expect(promptCalls).toBe(0)
   })
 
+  test("#given latest assistant turn has boolean finish === true #when checking blocks #then it is treated as terminal (NOT blocking)", async () => {
+    // given
+    let promptCalls = 0
+    const client = {
+      session: {
+        status: async () => ({ data: { ses_boolean_finish: { type: "idle" } } }),
+        messages: async () => ({
+          data: [
+            {
+              info: { id: "msg_user", role: "user" },
+              parts: [{ type: "text", text: "run work" }],
+            },
+            {
+              info: { id: "msg_assistant", role: "assistant", finish: true },
+              parts: [{ type: "text", text: "done" }],
+            },
+          ],
+        }),
+        promptAsync: async () => {
+          promptCalls += 1
+        },
+      },
+    }
+
+    // when
+    const result = await dispatchInternalPrompt({
+      mode: "async",
+      client,
+      sessionID: "ses_boolean_finish",
+      input: { path: { id: "ses_boolean_finish" }, body: { parts: [] } },
+      source: "test:boolean-finish",
+      settleMs: 0,
+      postDispatchHoldMs: 0,
+    })
+
+    // then
+    expect(result.status).toBe("dispatched")
+    expect(promptCalls).toBe(1)
+  })
+
+  test("#given latest assistant turn has info.time.completed but no finish field #when checking blocks #then it is treated as terminal", async () => {
+    // given
+    let promptCalls = 0
+    const client = {
+      session: {
+        status: async () => ({ data: { ses_completed_time: { type: "idle" } } }),
+        messages: async () => ({
+          data: [
+            {
+              info: { id: "msg_user", role: "user" },
+              parts: [{ type: "text", text: "run work" }],
+            },
+            {
+              info: { id: "msg_assistant", role: "assistant", time: { completed: 1_762_000_000_000 } },
+              parts: [{ type: "text", text: "done" }],
+            },
+          ],
+        }),
+        promptAsync: async () => {
+          promptCalls += 1
+        },
+      },
+    }
+
+    // when
+    const result = await dispatchInternalPrompt({
+      mode: "async",
+      client,
+      sessionID: "ses_completed_time",
+      input: { path: { id: "ses_completed_time" }, body: { parts: [] } },
+      source: "test:completed-time",
+      settleMs: 0,
+      postDispatchHoldMs: 0,
+    })
+
+    // then
+    expect(result.status).toBe("dispatched")
+    expect(promptCalls).toBe(1)
+  })
+
   test("#given internal user tail follows an assistant waiting on tools #when an internal promptAsync is requested #then no prompt is sent", async () => {
     // given
     let promptCalls = 0
diff --git a/src/shared/prompt-async-gate.ts b/src/shared/prompt-async-gate.ts
index 35dfca218..a54f98713 100644
--- a/src/shared/prompt-async-gate.ts
+++ b/src/shared/prompt-async-gate.ts
@@ -341,15 +341,36 @@ function messageRole(message: unknown): string | undefined {
   return typeof message.role === "string" ? message.role : undefined
 }
 
-function messageFinish(message: unknown): string | undefined {
+function messageFinish(message: unknown): string | true | undefined {
   if (!isRecord(message)) {
     return undefined
   }
   const info = message.info
-  if (isRecord(info) && typeof info.finish === "string") {
-    return info.finish
+  if (isRecord(info)) {
+    if (info.finish === true) {
+      return true
+    }
+    if (typeof info.finish === "string" && info.finish.length > 0) {
+      return info.finish
+    }
   }
-  return typeof message.finish === "string" ? message.finish : undefined
+  if (message.finish === true) {
+    return true
+  }
+  return typeof message.finish === "string" && message.finish.length > 0 ? message.finish : undefined
+}
+
+function messageCompleted(message: unknown): boolean {
+  if (!isRecord(message)) {
+    return false
+  }
+  const info = message.info
+  const time = isRecord(info) && isRecord(info.time) ? info.time : undefined
+  const completed = time?.completed
+  if (typeof completed === "number" && Number.isFinite(completed)) {
+    return true
+  }
+  return typeof completed === "string" && completed.length > 0
 }
 
 function toInternalInitiatorTextPartLike(part: unknown): InternalInitiatorTextPartLike {
@@ -419,7 +440,13 @@ function latestAssistantTurnBlocksInternalPrompt(messages: unknown[]): boolean {
     const message = messages[index]
     const role = messageRole(message)
     if (role === "assistant") {
+      if (messageCompleted(message)) {
+        return false
+      }
       const finish = messageFinish(message)
+      if (finish === true) {
+        return false
+      }
       if (finish === undefined || finish === "unknown") {
         return true
       }