fix(agent-core): stop loop after aborted tool run

szsip239 · vincentkoc · commit 25c5e393f264 · 2026-06-22T17:53:21.000+08:00
diff --git a/packages/agent-core/src/agent-loop.test.ts b/packages/agent-core/src/agent-loop.test.ts
@@ -767,6 +767,59 @@ describe("agentLoop tool termination", () => {
     expect(events.filter((event) => event.type === "tool_execution_start")).toHaveLength(1);
     expect(events.at(-1)).toMatchObject({ type: "agent_end" });
   });
+
+  it("does not request another model turn after a tool aborts the run", async () => {
+    const controller = new AbortController();
+    let streamCalls = 0;
+    const streamFn: StreamFn = () => {
+      streamCalls += 1;
+      if (streamCalls > 1) {
+        throw new Error("model was called after abort");
+      }
+      const stream = createAssistantMessageEventStream();
+      queueMicrotask(() => {
+        const message = makeAssistantMessage([
+          { type: "toolCall", id: "call-abort", name: "abort_tool", arguments: {} },
+        ]);
+        stream.push({ type: "done", reason: "toolUse", message });
+        stream.end();
+      });
+      return stream;
+    };
+    const abortTool: AgentTool = {
+      name: "abort_tool",
+      label: "abort_tool",
+      description: "Abort the active run",
+      parameters: Type.Object({}, { additionalProperties: false }),
+      execute: async () => {
+        controller.abort(new Error("user aborted"));
+        return {
+          content: [{ type: "text", text: "aborted" }],
+          details: { aborted: true },
+        };
+      },
+    };
+    const events: AgentEvent[] = [];
+
+    const messages = await runAgentLoop(
+      [{ role: "user", content: "abort during tool", timestamp: 1 }],
+      {
+        systemPrompt: "",
+        messages: [],
+        tools: [abortTool],
+      },
+      config,
+      (event) => {
+        events.push(event);
+      },
+      controller.signal,
+      streamFn,
+    );
+
+    expect(streamCalls).toBe(1);
+    expect(messages.map((message) => message.role)).toEqual(["user", "assistant", "toolResult"]);
+    expect(events.at(-1)).toMatchObject({ type: "agent_end" });
+  });
 });
 
 describe("agentLoop thinking state", () => {
diff --git a/packages/agent-core/src/agent-loop.ts b/packages/agent-core/src/agent-loop.ts
@@ -332,6 +332,10 @@ async function runLoop(
       }
 
       await emit({ type: "turn_end", message, toolResults });
+      if (signal?.aborted) {
+        await emit({ type: "agent_end", messages: newMessages });
+        return;
+      }
 
       const nextTurnContext = {
         message,

Original file line number	Diff line number	Diff line change
`@@ -332,6 +332,10 @@ async function runLoop(`
`332`	`332`	`}`
`333`	`333`
`334`	`334`	`await emit({ type: "turn_end", message, toolResults });`
	`335`	`+ if (signal?.aborted) {`
	`336`	`+ await emit({ type: "agent_end", messages: newMessages });`
	`337`	`+ return;`
	`338`	`+ }`
`335`	`339`
`336`	`340`	`const nextTurnContext = {`
`337`	`341`	`message,`