diff --git a/extensions/crabbox/src/crabbox-worker-heartbeat.ts b/extensions/crabbox/src/crabbox-worker-heartbeat.ts
index 655b7c321607..61edb7239c83 100644
--- a/extensions/crabbox/src/crabbox-worker-heartbeat.ts
+++ b/extensions/crabbox/src/crabbox-worker-heartbeat.ts
@@ -62,6 +62,7 @@ export function createCrabboxHeartbeatManager(dependencies: {
     const controller = new AbortController();
     entry.controller = controller;
     let result: SpawnResult;
+    const startedAt = Date.now();
     try {
       result = await dependencies.run(entry, controller.signal);
     } catch (error) {
@@ -93,7 +94,8 @@ export function createCrabboxHeartbeatManager(dependencies: {
     }
     if (!entry.failureWarned) {
       entry.failureWarned = true;
-      warn(entry, crabboxCommandError("heartbeat", result).message);
+      const message = crabboxCommandError("heartbeat", result).message;
+      warn(entry, message.replace("(timeout)", `(timeout after ${Date.now() - startedAt} ms)`));
     }
     schedule(entry);
   };
diff --git a/extensions/crabbox/src/crabbox-worker-provider.test.ts b/extensions/crabbox/src/crabbox-worker-provider.test.ts
index 9d2764888d6c..8dbc6bed7ddb 100644
--- a/extensions/crabbox/src/crabbox-worker-provider.test.ts
+++ b/extensions/crabbox/src/crabbox-worker-provider.test.ts
@@ -2097,6 +2097,39 @@ describe("Crabbox worker provider", () => {
     }
   });
 
+  it("reports the measured heartbeat duration when the command times out", async () => {
+    vi.useFakeTimers();
+    const warnings: string[] = [];
+    const provider = providerWithRunner(
+      async (argv) => {
+        if (argv[1] === "inspect") {
+          return commandResult({ stdout: inspectJson() });
+        }
+        if (argv[1] === "heartbeat") {
+          await new Promise<void>((resolve) => {
+            setTimeout(resolve, 60_012);
+          });
+          return commandResult({ code: null, killed: true, termination: "timeout" });
+        }
+        return commandResult();
+      },
+      (message) => warnings.push(message),
+    );
+    const lease = lifecycleLease();
+
+    try {
+      await expect(provider.inspect(lease)).resolves.toStrictEqual({ status: "active" });
+      await vi.advanceTimersByTimeAsync(60_012);
+
+      expect(warnings).toEqual([
+        "Crabbox heartbeat did not exit normally (timeout after 60012 ms); cloud worker machines may be reaped after 60m of coordinator-idle time",
+      ]);
+    } finally {
+      await provider.destroy(lease);
+      vi.useRealTimers();
+    }
+  });
+
   it("keeps heartbeat transport failures out of lifecycle operations and retries", async () => {
     vi.useFakeTimers();
     let heartbeatAttempts = 0;
diff --git a/src/gateway/server-methods/sessions-dispatch.ts b/src/gateway/server-methods/sessions-dispatch.ts
index 6ea009c766bc..3cbc1a9e4db9 100644
--- a/src/gateway/server-methods/sessions-dispatch.ts
+++ b/src/gateway/server-methods/sessions-dispatch.ts
@@ -171,7 +171,7 @@ async function validateDispatchExecutionMode(params: {
   }
   respondInvalidWorkerSession(
     params.respond,
-    `runtime ${params.sessionRuntime} requires an SSH-backed cloud worker provider; choose a provider that supports remote-exec, or select an agent/model route with agentRuntime.id "openclaw"`,
+    `selected cloud worker provider does not support the remote-exec execution mode required by runtime ${params.sessionRuntime}; use an approved paired device or a provider that advertises remote-exec`,
   );
   return false;
 }
diff --git a/src/gateway/server-methods/sessions.dispatch.test.ts b/src/gateway/server-methods/sessions.dispatch.test.ts
index 55fd1a476929..4d0730baeea5 100644
--- a/src/gateway/server-methods/sessions.dispatch.test.ts
+++ b/src/gateway/server-methods/sessions.dispatch.test.ts
@@ -437,7 +437,7 @@ describe("sessions.dispatch", () => {
       expect.objectContaining({
         code: ErrorCodes.INVALID_REQUEST,
         message:
-          'runtime codex requires an SSH-backed cloud worker provider; choose a provider that supports remote-exec, or select an agent/model route with agentRuntime.id "openclaw"',
+          "selected cloud worker provider does not support the remote-exec execution mode required by runtime codex; use an approved paired device or a provider that advertises remote-exec",
       }),
     );
   });