Avoid stale subagent reply carryover

src/agents/subagent-control.test.ts

@@ -172,15 +172,15 @@ describe("sendControlledSubagentMessage", () => {
 
     __testing.setDepsForTest({
       callGateway: async <T = Record<string, unknown>>(request: CallGatewayOptions) => {
+        if (request.method === "chat.history") {
+          return { messages: [] } as T;
+        }
         if (request.method === "agent") {
           return { runId: "run-followup-send" } as T;
         }
         if (request.method === "agent.wait") {
           return { status: "done" } as T;
         }
-        if (request.method === "chat.history") {
-          return { messages: [] } as T;
-        }
         throw new Error(`unexpected method: ${request.method}`);
       },
     });
@@ -247,15 +247,15 @@ describe("sendControlledSubagentMessage", () => {
 
     __testing.setDepsForTest({
       callGateway: async <T = Record<string, unknown>>(request: CallGatewayOptions) => {
+        if (request.method === "chat.history") {
+          return { messages: [] } as T;
+        }
         if (request.method === "agent") {
           return { runId: "run-followup-stale-send" } as T;
         }
         if (request.method === "agent.wait") {
           return { status: "done" } as T;
         }
-        if (request.method === "chat.history") {
-          return { messages: [] } as T;
-        }
         throw new Error(`unexpected method: ${request.method}`);
       },
     });
@@ -292,6 +292,77 @@ describe("sendControlledSubagentMessage", () => {
       replyText: undefined,
     });
   });
+
+  it("does not return the previous assistant reply when no new assistant message appears", async () => {
+    addSubagentRunForTests({
+      runId: "run-owned-stale-reply",
+      childSessionKey: "agent:main:subagent:owned-stale-reply",
+      controllerSessionKey: "agent:main:main",
+      requesterSessionKey: "agent:main:main",
+      requesterDisplayKey: "main",
+      task: "continue work",
+      cleanup: "keep",
+      createdAt: Date.now() - 5_000,
+      startedAt: Date.now() - 4_000,
+      endedAt: Date.now() - 1_000,
+      outcome: { status: "ok" },
+    });
+
+    let historyCalls = 0;
+    const staleAssistantMessage = {
+      role: "assistant",
+      content: [{ type: "text", text: "older reply from a previous run" }],
+    };
+
+    __testing.setDepsForTest({
+      callGateway: async <T = Record<string, unknown>>(request: CallGatewayOptions) => {
+        if (request.method === "chat.history") {
+          historyCalls += 1;
+          return { messages: [staleAssistantMessage] } as T;
+        }
+        if (request.method === "agent") {
+          return { runId: "run-followup-stale-reply" } as T;
+        }
+        if (request.method === "agent.wait") {
+          return { status: "done" } as T;
+        }
+        throw new Error(`unexpected method: ${request.method}`);
+      },
+    });
+
+    const result = await sendControlledSubagentMessage({
+      cfg: {
+        channels: { whatsapp: { allowFrom: ["*"] } },
+      } as OpenClawConfig,
+      controller: {
+        controllerSessionKey: "agent:main:main",
+        callerSessionKey: "agent:main:main",
+        callerIsSubagent: false,
+        controlScope: "children",
+      },
+      entry: {
+        runId: "run-owned-stale-reply",
+        childSessionKey: "agent:main:subagent:owned-stale-reply",
+        requesterSessionKey: "agent:main:main",
+        requesterDisplayKey: "main",
+        controllerSessionKey: "agent:main:main",
+        task: "continue work",
+        cleanup: "keep",
+        createdAt: Date.now() - 5_000,
+        startedAt: Date.now() - 4_000,
+        endedAt: Date.now() - 1_000,
+        outcome: { status: "ok" },
+      },
+      message: "continue",
+    });
+
+    expect(historyCalls).toBe(2);
+    expect(result).toEqual({
+      status: "ok",
+      runId: "run-followup-stale-reply",
+      replyText: undefined,
+    });
+  });
 });
 
 describe("killSubagentRunAdmin", () => {

src/agents/subagent-control.ts

@@ -50,6 +50,7 @@ export const MAX_RECENT_MINUTES = 24 * 60;
 export const MAX_STEER_MESSAGE_CHARS = 4_000;
 export const STEER_RATE_LIMIT_MS = 2_000;
 export const STEER_ABORT_SETTLE_TIMEOUT_MS = 5_000;
+const SUBAGENT_REPLY_HISTORY_LIMIT = 50;
 
 const steerRateLimit = new Map<string, number>();
 
@@ -195,6 +196,27 @@ export function isActiveSubagentRun(
   return !entry.endedAt || pendingDescendantCount(entry.childSessionKey) > 0;
 }
 
+function resolveLatestAssistantReplySnapshot(messages: unknown[]): {
+  text?: string;
+  fingerprint?: string;
+} {
+  for (let index = messages.length - 1; index >= 0; index -= 1) {
+    const message = messages[index];
+    const text = extractAssistantText(message);
+    if (!text) {
+      continue;
+    }
+    let fingerprint: string | undefined;
+    try {
+      fingerprint = JSON.stringify(message);
+    } catch {
+      fingerprint = text;
+    }
+    return { text, fingerprint };
+  }
+  return {};
+}
+
 function resolveRunStatus(entry: SubagentRunRecord, options?: { pendingDescendants?: number }) {
   const pendingDescendants = Math.max(0, options?.pendingDescendants ?? 0);
   if (pendingDescendants > 0) {
@@ -879,6 +901,14 @@ export async function sendControlledSubagentMessage(params: {
   const idempotencyKey = crypto.randomUUID();
   let runId: string = idempotencyKey;
   try {
+    const historyBefore = await subagentControlDeps.callGateway<{ messages: Array<unknown> }>({
+      method: "chat.history",
+      params: { sessionKey: targetSessionKey, limit: SUBAGENT_REPLY_HISTORY_LIMIT },
+    });
+    const baselineReply = resolveLatestAssistantReplySnapshot(
+      stripToolMessages(Array.isArray(historyBefore?.messages) ? historyBefore.messages : []),
+    );
+
     const response = await subagentControlDeps.callGateway<{ runId: string }>({
       method: "agent",
       params: {
@@ -914,11 +944,15 @@ export async function sendControlledSubagentMessage(params: {
 
     const history = await subagentControlDeps.callGateway<{ messages: Array<unknown> }>({
       method: "chat.history",
-      params: { sessionKey: targetSessionKey, limit: 50 },
+      params: { sessionKey: targetSessionKey, limit: SUBAGENT_REPLY_HISTORY_LIMIT },
     });
-    const filtered = stripToolMessages(Array.isArray(history?.messages) ? history.messages : []);
-    const last = filtered.length > 0 ? filtered[filtered.length - 1] : undefined;
-    const replyText = last ? extractAssistantText(last) : undefined;
+    const latestReply = resolveLatestAssistantReplySnapshot(
+      stripToolMessages(Array.isArray(history?.messages) ? history.messages : []),
+    );
+    const replyText =
+      latestReply.text && latestReply.fingerprint !== baselineReply.fingerprint
+        ? latestReply.text
+        : undefined;
     return { status: "ok" as const, runId, replyText };
   } catch (err) {
     const error = err instanceof Error ? err.message : String(err);