diff --git a/dist-exe/cc-web-bun-linux-x64-baseline.tar.gz b/dist-exe/cc-web-bun-linux-x64-baseline.tar.gz
index 4ef0dff..7bdad05 100644
Binary files a/dist-exe/cc-web-bun-linux-x64-baseline.tar.gz and b/dist-exe/cc-web-bun-linux-x64-baseline.tar.gz differ
diff --git a/lib/javascript-session-runtime.js b/lib/javascript-session-runtime.js
index 8dd65c7..3b9995c 100644
--- a/lib/javascript-session-runtime.js
+++ b/lib/javascript-session-runtime.js
@@ -124,6 +124,16 @@ const CONVERSATION_STATUSES = new Set(['running', 'waiting_for_children', 'idle'
 const EVENT_POLL_INTERVAL_MS = 100;
 const IDLE_EVENT_STABILITY_MS = 250;
 
+function errorFromPayload(payload) {
+  const error = new Error(String(payload?.message || payload?.code || 'ccweb 脚本调用失败'));
+  error.code = String(payload?.code || 'script_call_failed');
+  error.details = payload && typeof payload === 'object' ? { ...payload } : {};
+  delete error.details.ok;
+  delete error.details.code;
+  delete error.details.message;
+  return error;
+}
+
 function localError(code, message, details = {}) {
   const error = new Error(message);
   error.code = code;
diff --git a/scripts/javascript-session-runtime-unit.js b/scripts/javascript-session-runtime-unit.js
index e1ef210..7f55254 100644
--- a/scripts/javascript-session-runtime-unit.js
+++ b/scripts/javascript-session-runtime-unit.js
@@ -67,7 +67,9 @@ async function main() {
           response = { ok: true, conversationId: payload.sourceSessionId };
           break;
         case 'ccweb_script_get_last_message':
-          response = { ok: true, conversationId: payload.args.conversationId, message: '服务端最后消息' };
+          response = payload.args.conversationId === 'error-test'
+            ? { ok: false, code: 'conversation_not_found', message: '目标对话不存在。', conversationId: 'error-test' }
+            : { ok: true, conversationId: payload.args.conversationId, message: '服务端最后消息' };
           break;
         case 'ccweb_script_get_conversation_status':
           statusCallCount += 1;
@@ -156,6 +158,24 @@ async function main() {
     assert.equal(succeeded.stderr, '');
     assert.equal(notifications.length, 0);
 
+    assert.equal(runtime.writeScript({
+      name: 'error.js',
+      content: [
+        "import { getLastMessage } from '@ccweb/session';",
+        "try { await getLastMessage('error-test'); } catch (error) {",
+        "  console.log(JSON.stringify({ name: error.name, code: error.code, message: error.message, details: error.details }));",
+        '}',
+      ].join('\n'),
+    }, sourceId).ok, true);
+    const errorStart = runtime.runScript({ name: 'error.js' }, sourceId);
+    const errorRun = await waitForRun(runtime, sourceId, errorStart.runId, (run) => run.status === 'succeeded');
+    assert.equal(errorRun.exitCode, 0);
+    const errorResult = JSON.parse(errorRun.stdout.trim());
+    assert.equal(errorResult.name, 'Error');
+    assert.equal(errorResult.code, 'conversation_not_found');
+    assert.equal(errorResult.message, '目标对话不存在。');
+    assert.equal(errorResult.details.conversationId, 'error-test');
+
     assert.equal(runtime.writeScript({ name: 'failed.js', content: "console.error('expected failure'); process.exit(3);" }, sourceId).ok, true);
     const failedStart = runtime.runScript({ name: 'failed.js' }, sourceId);
     const failed = await waitForRun(runtime, sourceId, failedStart.runId, (run) => run.status === 'failed');