fix(session): recover cursor reasonless tool aborts

Scoped the Cursor server-execution marker gate to the stream-stall path so an unmarked client-side Cursor tool call (todo/MCP) followed by a reasonless abort recovers via its synthetic executed:false result instead of settling the turn. Fixes #6668
2026-07-26 04:33:34 +00:00
parent 464eba46b3
commit 0988efbce6
2 changed files with 126 additions and 0 deletions
@@ -850,10 +850,18 @@ export class TurnRecovery {
 		if (!reasonlessAbort && !streamStall) return undefined;
 		if (reasonlessAbort && genericAbort) message.errorId = AIError.create(AIError.Flag.Abort);

+		// The Cursor server-execution marker gate applies only to the stream-stall
+		// path: an unmarked/unresolved Cursor block there means the server has not
+		// finished executing, so resuming would race it. A reasonless abort instead
+		// ends the turn and the agent loop pairs every un-run call (Cursor's unmarked
+		// `todo`/MCP blocks included) with a synthetic `executed: false` result, so
+		// the tool-result reconciliation below is the safety gate and the marker is
+		// irrelevant.
 		const resolvedToolCallIds: string[] = [];
 		for (const block of message.content) {
 			if (block.type !== "toolCall") continue;
 			if (
+				streamStall &&
 				message.provider === "cursor" &&
 				(!(kCursorExecResolved in block) || block[kCursorExecResolved] !== true)
 			) {
@@ -1006,6 +1006,124 @@ describe("AgentSession retry delay cap", () => {
 		expect(retryEndEvents).toContainEqual(expect.objectContaining({ success: true, attempt: 1 }));
 		expect(lastAssistant(session).content).toContainEqual({ type: "text", text: "Recovered after Cursor stall" });
 	});
+	it("resumes a Cursor reasonless abort after an unmarked client-side tool call", async () => {
+		const model = createMockModel({
+			id: "composer-2.5",
+			provider: "cursor",
+		});
+		authStorage.setRuntimeApiKey("cursor", "cursor-test-key");
+		// Cursor emits `todo` client-side without the server-execution marker; a
+		// reasonless abort after it must still recover (issue #6668 review).
+		const toolCall: ToolCall = {
+			type: "toolCall",
+			id: "cursor-todo-1",
+			name: "todo",
+			arguments: { ops: [] },
+		};
+		let streamCalls = 0;
+		let resumedWithSyntheticResult = false;
+		const agent = new Agent({
+			getApiKey: requestedModel => `${requestedModel.provider}-test-key`,
+			initialState: {
+				model,
+				systemPrompt: ["Test"],
+				tools: [],
+				messages: [],
+			},
+			streamFn: (_requestedModel, context, options) => {
+				streamCalls += 1;
+				if (streamCalls > 1) {
+					const matchingResult = context.messages.find(
+						message => message.role === "toolResult" && message.toolCallId === toolCall.id,
+					);
+					resumedWithSyntheticResult =
+						matchingResult?.role === "toolResult" &&
+						typeof matchingResult.details === "object" &&
+						matchingResult.details !== null &&
+						"executed" in matchingResult.details &&
+						matchingResult.details.executed === false;
+					model.push({ content: ["Recovered after Cursor reasonless abort"] });
+					return model.stream(model, context, options);
+				}
+
+				const stream = new AssistantMessageEventStream();
+				queueMicrotask(() => {
+					const partial: AssistantMessage = {
+						role: "assistant",
+						content: [toolCall],
+						api: model.api,
+						provider: model.provider,
+						model: model.id,
+						usage: {
+							input: 0,
+							output: 0,
+							cacheRead: 0,
+							cacheWrite: 0,
+							totalTokens: 0,
+							cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+						},
+						stopReason: "stop",
+						timestamp: Date.now(),
+					};
+					stream.push({ type: "start", partial });
+					stream.push({ type: "toolcall_start", contentIndex: 0, partial });
+					stream.push({
+						type: "toolcall_delta",
+						contentIndex: 0,
+						delta: JSON.stringify(toolCall.arguments),
+						partial,
+					});
+					stream.push({ type: "toolcall_end", contentIndex: 0, toolCall, partial });
+					stream.push({
+						type: "error",
+						reason: "aborted",
+						error: {
+							...partial,
+							stopReason: "aborted",
+							errorMessage: "Request was aborted",
+						},
+					});
+				});
+				return stream;
+			},
+		});
+
+		const settings = Settings.isolated({
+			"compaction.enabled": false,
+			"retry.baseDelayMs": 5,
+			"retry.maxRetries": 1,
+		});
+		settings.setModelRole("default", `${model.provider}/${model.id}`);
+		session = new AgentSession({
+			agent,
+			sessionManager: SessionManager.inMemory(),
+			settings,
+			modelRegistry,
+		});
+		const retryStartEvents: AutoRetryStartEvent[] = [];
+		const retryEndEvents: AutoRetryEndEvent[] = [];
+		session.subscribe(event => {
+			if (event.type === "auto_retry_start") retryStartEvents.push(event);
+			if (event.type === "auto_retry_end") retryEndEvents.push(event);
+		});
+
+		await session.prompt("Update the todo list");
+		await session.waitForIdle();
+
+		expect(streamCalls).toBe(2);
+		expect(resumedWithSyntheticResult).toBe(true);
+		expect(
+			session.agent.state.messages.filter(
+				message => message.role === "toolResult" && message.toolCallId === toolCall.id,
+			),
+		).toHaveLength(1);
+		expect(retryStartEvents).toHaveLength(1);
+		expect(retryEndEvents).toContainEqual(expect.objectContaining({ success: true, attempt: 1 }));
+		expect(lastAssistant(session).content).toContainEqual({
+			type: "text",
+			text: "Recovered after Cursor reasonless abort",
+		});
+	});

 	it("retries a transient socket close after partial text and thinking", async () => {
 		const model = getBundledModel("anthropic", "claude-sonnet-4-5");