diff --git a/CHANGELOG.md b/CHANGELOG.md
index 88fd873ccfe..393ed45ed86 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -39,6 +39,7 @@ Docs: https://docs.openclaw.ai
 - Kimi Coding/Anthropic tools compatibility: normalize `anthropic-messages` tool payloads to OpenAI-style `tools[].function` + compatible `tool_choice` when targeting Kimi Coding endpoints, restoring tool-call workflows that regressed after v2026.3.2. (#37038) Thanks @mochimochimochi-hub.
 - Heartbeat/workspace-path guardrails: append explicit workspace `HEARTBEAT.md` path guidance (and `docs/heartbeat.md` avoidance) to heartbeat prompts so heartbeat runs target workspace checklists reliably across packaged install layouts. (#37037) Thanks @stofancy.
 - Subagents/kill-complete announce race: when a late `subagent-complete` lifecycle event arrives after an earlier kill marker, clear stale kill suppression/cleanup flags and re-run announce cleanup so finished runs no longer get silently swallowed. (#37024) Thanks @cmfinlan.
+- Agents/tool-result cleanup timeout hardening: on embedded runner teardown idle timeouts, clear pending tool-call state without persisting synthetic `missing tool result` entries, preventing timeout cleanups from poisoning follow-up turns; adds regression coverage for timeout clear-vs-flush behavior. (#37081) Thanks @Coyote-Den.
 - Cron/OpenAI Codex OAuth refresh hardening: when `openai-codex` token refresh fails specifically on account-id extraction, reuse the cached access token instead of failing the run immediately, with regression coverage to keep non-Codex and unrelated refresh failures unchanged. (#36604) Thanks @laulopezreal.
 - Gateway/remote WS break-glass hostname support: honor `OPENCLAW_ALLOW_INSECURE_PRIVATE_WS=1` for `ws://` hostname URLs (not only private IP literals) across onboarding validation and runtime gateway connection checks, while still rejecting public IP literals and non-unicast IPv6 endpoints. (#36930) Thanks @manju-rn.
 - Routing/binding lookup scalability: pre-index route bindings by channel/account and avoid full binding-list rescans on channel-account cache rollover, preventing multi-second `resolveAgentRoute` stalls in large binding configurations. (#36915) Thanks @songchenghao.
diff --git a/src/agents/pi-embedded-runner.guard.waitforidle-before-flush.test.ts b/src/agents/pi-embedded-runner.guard.waitforidle-before-flush.test.ts
index d0396039632..207e721ac81 100644
--- a/src/agents/pi-embedded-runner.guard.waitforidle-before-flush.test.ts
+++ b/src/agents/pi-embedded-runner.guard.waitforidle-before-flush.test.ts
@@ -97,6 +97,33 @@ describe("flushPendingToolResultsAfterIdle", () => {
     );
   });
 
+  it("clears pending without synthetic flush when timeout cleanup is requested", async () => {
+    const sm = guardSessionManager(SessionManager.inMemory());
+    const appendMessage = sm.appendMessage.bind(sm) as unknown as (message: AgentMessage) => void;
+    vi.useFakeTimers();
+    const agent = { waitForIdle: () => new Promise<void>(() => {}) };
+
+    appendMessage(assistantToolCall("call_orphan_2"));
+
+    const flushPromise = flushPendingToolResultsAfterIdle({
+      agent,
+      sessionManager: sm,
+      timeoutMs: 30,
+      clearPendingOnTimeout: true,
+    });
+    await vi.advanceTimersByTimeAsync(30);
+    await flushPromise;
+
+    expect(getMessages(sm).map((m) => m.role)).toEqual(["assistant"]);
+
+    appendMessage({
+      role: "user",
+      content: "still there?",
+      timestamp: Date.now(),
+    } as AgentMessage);
+    expect(getMessages(sm).map((m) => m.role)).toEqual(["assistant", "user"]);
+  });
+
   it("clears timeout handle when waitForIdle resolves first", async () => {
     const sm = guardSessionManager(SessionManager.inMemory());
     vi.useFakeTimers();
diff --git a/src/agents/pi-embedded-runner/compact.ts b/src/agents/pi-embedded-runner/compact.ts
index 1742c554033..2bfc9e0a5ce 100644
--- a/src/agents/pi-embedded-runner/compact.ts
+++ b/src/agents/pi-embedded-runner/compact.ts
@@ -817,6 +817,7 @@ export async function compactEmbeddedPiSessionDirect(
         await flushPendingToolResultsAfterIdle({
           agent: session?.agent,
           sessionManager,
+          clearPendingOnTimeout: true,
         });
         session.dispose();
       }
diff --git a/src/agents/pi-embedded-runner/run/attempt.ts b/src/agents/pi-embedded-runner/run/attempt.ts
index e19dd3cedb2..56223333ccf 100644
--- a/src/agents/pi-embedded-runner/run/attempt.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.ts
@@ -1338,6 +1338,7 @@ export async function runEmbeddedAttempt(
         await flushPendingToolResultsAfterIdle({
           agent: activeSession?.agent,
           sessionManager,
+          clearPendingOnTimeout: true,
         });
         activeSession.dispose();
         throw err;
@@ -1904,6 +1905,7 @@ export async function runEmbeddedAttempt(
       await flushPendingToolResultsAfterIdle({
         agent: session?.agent,
         sessionManager,
+        clearPendingOnTimeout: true,
       });
       session?.dispose();
       releaseWsSession(params.sessionId);
diff --git a/src/agents/pi-embedded-runner/wait-for-idle-before-flush.ts b/src/agents/pi-embedded-runner/wait-for-idle-before-flush.ts
index c3cefd7d17e..71b661aadb7 100644
--- a/src/agents/pi-embedded-runner/wait-for-idle-before-flush.ts
+++ b/src/agents/pi-embedded-runner/wait-for-idle-before-flush.ts
@@ -4,6 +4,7 @@ type IdleAwareAgent = {
 
 type ToolResultFlushManager = {
   flushPendingToolResults?: (() => void) | undefined;
+  clearPendingToolResults?: (() => void) | undefined;
 };
 
 export const DEFAULT_WAIT_FOR_IDLE_TIMEOUT_MS = 30_000;
@@ -11,23 +12,27 @@ export const DEFAULT_WAIT_FOR_IDLE_TIMEOUT_MS = 30_000;
 async function waitForAgentIdleBestEffort(
   agent: IdleAwareAgent | null | undefined,
   timeoutMs: number,
-): Promise<void> {
+): Promise<boolean> {
   const waitForIdle = agent?.waitForIdle;
   if (typeof waitForIdle !== "function") {
-    return;
+    return false;
   }
 
+  const idleResolved = Symbol("idle");
+  const idleTimedOut = Symbol("timeout");
   let timeoutHandle: ReturnType<typeof setTimeout> | undefined;
   try {
-    await Promise.race([
-      waitForIdle.call(agent),
-      new Promise<void>((resolve) => {
-        timeoutHandle = setTimeout(resolve, timeoutMs);
+    const outcome = await Promise.race([
+      waitForIdle.call(agent).then(() => idleResolved),
+      new Promise<symbol>((resolve) => {
+        timeoutHandle = setTimeout(() => resolve(idleTimedOut), timeoutMs);
         timeoutHandle.unref?.();
       }),
     ]);
+    return outcome === idleTimedOut;
   } catch {
     // Best-effort during cleanup.
+    return false;
   } finally {
     if (timeoutHandle) {
       clearTimeout(timeoutHandle);
@@ -39,7 +44,15 @@ export async function flushPendingToolResultsAfterIdle(opts: {
   agent: IdleAwareAgent | null | undefined;
   sessionManager: ToolResultFlushManager | null | undefined;
   timeoutMs?: number;
+  clearPendingOnTimeout?: boolean;
 }): Promise<void> {
-  await waitForAgentIdleBestEffort(opts.agent, opts.timeoutMs ?? DEFAULT_WAIT_FOR_IDLE_TIMEOUT_MS);
+  const timedOut = await waitForAgentIdleBestEffort(
+    opts.agent,
+    opts.timeoutMs ?? DEFAULT_WAIT_FOR_IDLE_TIMEOUT_MS,
+  );
+  if (timedOut && opts.clearPendingOnTimeout && opts.sessionManager?.clearPendingToolResults) {
+    opts.sessionManager.clearPendingToolResults();
+    return;
+  }
   opts.sessionManager?.flushPendingToolResults?.();
 }
diff --git a/src/agents/session-tool-result-guard-wrapper.ts b/src/agents/session-tool-result-guard-wrapper.ts
index 8570bdd1687..c9ca8899712 100644
--- a/src/agents/session-tool-result-guard-wrapper.ts
+++ b/src/agents/session-tool-result-guard-wrapper.ts
@@ -9,6 +9,8 @@ import { installSessionToolResultGuard } from "./session-tool-result-guard.js";
 export type GuardedSessionManager = SessionManager & {
   /** Flush any synthetic tool results for pending tool calls. Idempotent. */
   flushPendingToolResults?: () => void;
+  /** Clear pending tool calls without persisting synthetic tool results. Idempotent. */
+  clearPendingToolResults?: () => void;
 };
 
 /**
@@ -69,5 +71,6 @@ export function guardSessionManager(
     beforeMessageWriteHook: beforeMessageWrite,
   });
   (sessionManager as GuardedSessionManager).flushPendingToolResults = guard.flushPendingToolResults;
+  (sessionManager as GuardedSessionManager).clearPendingToolResults = guard.clearPendingToolResults;
   return sessionManager as GuardedSessionManager;
 }
diff --git a/src/agents/session-tool-result-guard.test.ts b/src/agents/session-tool-result-guard.test.ts
index e7366785cea..36e06d52dec 100644
--- a/src/agents/session-tool-result-guard.test.ts
+++ b/src/agents/session-tool-result-guard.test.ts
@@ -111,6 +111,17 @@ describe("installSessionToolResultGuard", () => {
     expectPersistedRoles(sm, ["assistant", "toolResult"]);
   });
 
+  it("clears pending tool calls without inserting synthetic tool results", () => {
+    const sm = SessionManager.inMemory();
+    const guard = installSessionToolResultGuard(sm);
+
+    sm.appendMessage(toolCallMessage);
+    guard.clearPendingToolResults();
+
+    expectPersistedRoles(sm, ["assistant"]);
+    expect(guard.getPendingIds()).toEqual([]);
+  });
+
   it("clears pending on user interruption when synthetic tool results are disabled", () => {
     const sm = SessionManager.inMemory();
     const guard = installSessionToolResultGuard(sm, {
diff --git a/src/agents/session-tool-result-guard.ts b/src/agents/session-tool-result-guard.ts
index 4ec5fe6c8cb..cb5d465754e 100644
--- a/src/agents/session-tool-result-guard.ts
+++ b/src/agents/session-tool-result-guard.ts
@@ -104,6 +104,7 @@ export function installSessionToolResultGuard(
   },
 ): {
   flushPendingToolResults: () => void;
+  clearPendingToolResults: () => void;
   getPendingIds: () => string[];
 } {
   const originalAppend = sessionManager.appendMessage.bind(sessionManager);
@@ -164,6 +165,10 @@ export function installSessionToolResultGuard(
     pendingState.clear();
   };
 
+  const clearPendingToolResults = () => {
+    pendingState.clear();
+  };
+
   const guardedAppend = (message: AgentMessage) => {
     let nextMessage = message;
     const role = (message as { role?: unknown }).role;
@@ -255,6 +260,7 @@ export function installSessionToolResultGuard(
 
   return {
     flushPendingToolResults,
+    clearPendingToolResults,
     getPendingIds: pendingState.getPendingIds,
   };
 }