fix: reject stale ACP reconnect prompts

CHANGELOG.md

@@ -38,6 +38,7 @@ Docs: https://docs.openclaw.ai
 - MS Teams/streaming: strip already-streamed text from fallback block delivery when replies exceed the 4000-character streaming limit so long responses stop duplicating content. (#59297) Thanks @bradgroux.
 - MS Teams/logging: format non-`Error` failures with the shared unknown-error helper so logs stop collapsing caught SDK or Axios objects into `[object Object]`. (#59321) Thanks @bradgroux.
 - Slack/thread context: filter thread starter and history by the effective conversation allowlist without dropping valid open-room, DM, or group DM context. (#58380)
+- ACP/gateway reconnects: reject stale pre-ack ACP prompts after reconnect grace expiry so callers fail cleanly instead of hanging indefinitely when the gateway never confirms the run.
 
 ## 2026.4.1-beta.1
 

src/acp/translator.stop-reason.test.ts

@@ -402,7 +402,7 @@ describe("acp translator stop reason mapping", () => {
     }
   });
 
-  it("keeps pre-ack prompts pending after reconnect timeout", async () => {
+  it("rejects pre-ack prompts when reconnect timeout still finds no run", async () => {
     vi.useFakeTimers();
     try {
       const sessionId = "session-1";
@@ -442,9 +442,7 @@ describe("acp translator stop reason mapping", () => {
       );
 
       await vi.advanceTimersByTimeAsync(5_000);
-      await expect(Promise.race([promptPromise, Promise.resolve("pending")])).resolves.toBe(
-        "pending",
-      );
+      await expect(promptPromise).rejects.toThrow("Gateway disconnected: 1006: connection lost");
     } finally {
       vi.useRealTimers();
     }
@@ -491,7 +489,7 @@ describe("acp translator stop reason mapping", () => {
     await expect(Promise.race([secondPrompt, Promise.resolve("pending")])).resolves.toBe("pending");
   });
 
-  it("keeps disconnect deadline when a superseded send resolves late", async () => {
+  it("rejects stale pre-ack prompts when a superseded send resolves late", async () => {
     vi.useFakeTimers();
     try {
       const sessionId = "session-1";
@@ -548,15 +546,13 @@ describe("acp translator stop reason mapping", () => {
       agent.handleGatewayReconnect();
       await vi.advanceTimersByTimeAsync(5_000);
 
-      await expect(Promise.race([secondPrompt, Promise.resolve("pending")])).resolves.toBe(
-        "pending",
-      );
+      await expect(secondPrompt).rejects.toThrow("Gateway disconnected: 1006: connection lost");
     } finally {
       vi.useRealTimers();
     }
   });
 
-  it("finishes terminal prompts without rejecting other reconnecting prompts", async () => {
+  it("finishes terminal prompts while rejecting stale pre-ack prompts", async () => {
     vi.useFakeTimers();
     try {
       let acceptedRunId: string | undefined;
@@ -621,9 +617,7 @@ describe("acp translator stop reason mapping", () => {
       await vi.advanceTimersByTimeAsync(5_000);
 
       await expect(acceptedPrompt).resolves.toEqual({ stopReason: "end_turn" });
-      await expect(Promise.race([preAckPrompt, Promise.resolve("pending")])).resolves.toBe(
-        "pending",
-      );
+      await expect(preAckPrompt).rejects.toThrow("Gateway disconnected: 1006: connection lost");
     } finally {
       vi.useRealTimers();
     }

src/acp/translator.ts

@@ -1088,6 +1088,17 @@ export class AcpGatewayAgent implements Agent {
     pending.disconnectContext = undefined;
   }
 
+  private shouldRejectPendingAtDisconnectDeadline(
+    pending: PendingPrompt,
+    disconnectContext: DisconnectContext,
+  ): boolean {
+    return (
+      pending.disconnectContext === disconnectContext &&
+      (!pending.sendAccepted ||
+        this.activeDisconnectContext?.generation === disconnectContext.generation)
+    );
+  }
+
   private async reconcilePendingPrompts(
     observedDisconnectGeneration: number,
     deadlineExpired: boolean,
@@ -1101,8 +1112,6 @@ export class AcpGatewayAgent implements Agent {
 
     const pendingEntries = [...this.pendingPrompts.entries()];
     let keepDisconnectTimer = false;
-    const shouldRejectPending =
-      deadlineExpired && this.activeDisconnectContext?.generation === observedDisconnectGeneration;
     for (const [sessionId, pending] of pendingEntries) {
       if (this.pendingPrompts.get(sessionId) !== pending) {
         continue;
@@ -1114,7 +1123,6 @@ export class AcpGatewayAgent implements Agent {
         sessionId,
         pending,
         deadlineExpired,
-        shouldRejectPending,
       );
       if (shouldKeepPending) {
         keepDisconnectTimer = true;
@@ -1130,7 +1138,6 @@ export class AcpGatewayAgent implements Agent {
     sessionId: string,
     pending: PendingPrompt,
     deadlineExpired: boolean,
-    shouldRejectPending: boolean,
   ): Promise<boolean> {
     const disconnectContext = pending.disconnectContext;
     if (!disconnectContext) {
@@ -1149,7 +1156,7 @@ export class AcpGatewayAgent implements Agent {
     } catch (err) {
       this.log(`agent.wait reconcile failed for ${pending.idempotencyKey}: ${String(err)}`);
       if (deadlineExpired) {
-        if (shouldRejectPending) {
+        if (this.shouldRejectPendingAtDisconnectDeadline(pending, disconnectContext)) {
           this.rejectPendingPrompt(
             pending,
             new Error(`Gateway disconnected: ${disconnectContext.reason}`),
@@ -1175,7 +1182,7 @@ export class AcpGatewayAgent implements Agent {
       return false;
     }
     if (deadlineExpired) {
-      if (shouldRejectPending) {
+      if (this.shouldRejectPendingAtDisconnectDeadline(currentPending, disconnectContext)) {
         const currentDisconnectContext = currentPending.disconnectContext;
         if (!currentDisconnectContext) {
           return false;