fix(coding-agent): close terminal retry lifecycle

packages/coding-agent/src/session/agent-session.ts

@@ -2232,8 +2232,8 @@ export class AgentSession {
 		const prewalk = this.#prewalk;
 		if (!prewalk || context?.message.role !== "assistant") return;
 
-		const todoCalledThisTurn = context.toolResults.some(result => result.toolName === "todo");
-		if (todoCalledThisTurn) {
+		const todoSucceededThisTurn = context.toolResults.some(result => result.toolName === "todo" && !result.isError);
+		if (todoSucceededThisTurn) {
 			this.#prewalkTodoSeen = true;
 		}
 
@@ -2268,9 +2268,6 @@ export class AgentSession {
 		// not establish the list. The gate keys on the ACTIVE tool set, not the
 		// registry: a registered-but-deactivated todo (e.g. a restricted
 		// active-tool slate) is uncallable and would deadlock the switch.
-		if (context.toolResults.some(result => result.toolName === "todo" && !result.isError)) {
-			this.#prewalkTodoSeen = true;
-		}
 		const todoGateOpen = this.#prewalkTodoSeen || !this.getActiveToolNames().includes("todo");
 		const action = todoGateOpen
 			? context.toolResults.find(result => PREWALK_ACTION_TOOLS[result.toolName])
@@ -4584,6 +4581,17 @@ export class AgentSession {
 			if (this.#isClassifierRefusal(msg)) {
 				this.#removeAssistantMessageFromActiveContext(msg);
 			}
+			if (msg.stopReason === "error" && this.#retryAttempt > 0) {
+				const attempt = this.#retryAttempt;
+				this.#retryAttempt = 0;
+				await this.#emitSessionEvent({
+					type: "auto_retry_end",
+					success: false,
+					attempt,
+					finalError: msg.errorMessage,
+				});
+				this.#clearPendingRecoveredRetryErrors();
+			}
 			this.#resolveRetry();
 
 			if (!checkedCompaction) {

packages/coding-agent/test/agent-session-prewalk.test.ts

@@ -241,7 +241,11 @@ describe("AgentSession prewalk", () => {
 		const failingTodoTool: AgentTool<typeof todoToolSchema, undefined> = {
 			...todoTool,
 			async execute() {
-				throw new Error("todo update failed");
+				return {
+					content: [{ type: "text", text: "todo update failed" }],
+					details: undefined,
+					isError: true,
+				};
 			},
 		};
 		const mock = createMockModel({

packages/coding-agent/test/agent-session-retry-fallback.test.ts

@@ -1683,6 +1683,54 @@ describe("AgentSession retry fallback", () => {
 		expect(lastAssistant.errorMessage).toBe(envelopeError);
 	});
 
+	it("closes the retry lifecycle when a retried turn ends with a non-retryable error", async () => {
+		const model = getBundledModel("openai", "gpt-4o-mini");
+		if (!model) throw new Error("Expected bundled OpenAI test model to exist");
+
+		const retryableError = "rate limit exceeded retry-after-ms=5";
+		const terminalError = "invalid request: schema violation";
+		const requestedModels: string[] = [];
+		const mock = createMockModel();
+		const agent = new Agent({
+			getApiKey: requestedModel => `${requestedModel.provider}-test-key`,
+			initialState: {
+				model,
+				systemPrompt: ["Test"],
+				tools: [],
+				messages: [],
+			},
+			streamFn: (requestedModel, context, options) => {
+				requestedModels.push(`${requestedModel.provider}/${requestedModel.id}`);
+				mock.push({ throw: requestedModels.length === 1 ? retryableError : terminalError });
+				return mock.stream(requestedModel, context, options);
+			},
+		});
+		const settings = Settings.isolated({
+			"compaction.enabled": false,
+			"retry.baseDelayMs": 5,
+			"retry.maxRetries": 1,
+		});
+		session = new AgentSession({
+			agent,
+			sessionManager: SessionManager.inMemory(),
+			settings,
+			modelRegistry,
+		});
+		const { retryStartEvents, retryEndEvents } = trackRetryEvents(session);
+		vi.spyOn(scheduler, "wait").mockResolvedValue(undefined);
+
+		await session.prompt("Retry once, then surface a terminal validation failure");
+		await session.waitForIdle();
+
+		expect(requestedModels).toEqual([`${model.provider}/${model.id}`, `${model.provider}/${model.id}`]);
+		expect(retryStartEvents).toHaveLength(1);
+		expect(retryEndEvents).toEqual([
+			expect.objectContaining({ success: false, attempt: 1, finalError: terminalError }),
+		]);
+		expect(session.retryAttempt).toBe(0);
+		expect(getLastAssistantMessage(session).stopReason).toBe("error");
+	});
+
 	it("auto-retries a bare Request was aborted error-stop turn (issue #5375)", async () => {
 		const model = getBundledModel("openai", "gpt-4o-mini");
 		if (!model) {