fix(collab-web): surface terminal auto_retry_end failures

(cherry picked from commit 6a6c4014158d9636ed0e030837633ad313c1aa5a)

packages/collab-web/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed the agent appearing to stop silently with no message: terminal `auto_retry_end` failures now surface as an error notice instead of being discarded.
+
 ## [17.1.0] - 2026-07-24
 
 ### Fixed

packages/collab-web/src/lib/client.ts

@@ -454,6 +454,9 @@ export class GuestClient {
 			case "auto_retry_start":
 				this.#pushNotice("info", `retry ${event.attempt}/${event.maxAttempts}: ${event.errorMessage}`);
 				break;
+			case "auto_retry_end":
+				if (!event.success) this.#pushNotice("error", event.finalError ?? "retry failed");
+				break;
 			case "auto_compaction_start":
 				this.#pushNotice("info", `compacting context (${event.reason})`);
 				break;

packages/collab-web/test/client.test.ts

@@ -234,6 +234,17 @@ describe("GuestClient frame apply", () => {
 		expect(notices[0]).toMatchObject({ level: "error", message: "boom" });
 	});
 
+	it("auto_retry_end failure surfaces an error notice", () => {
+		const client = liveClient();
+		client.applyFrameForTest({
+			t: "event",
+			event: { type: "auto_retry_end", success: false, attempt: 3, finalError: "x" },
+		});
+		const notices = client.getSnapshot().notices;
+		expect(notices).toHaveLength(1);
+		expect(notices[0]).toMatchObject({ level: "error", message: "x" });
+	});
+
 	it("a pre-welcome error (hello rejection, e.g. protocol mismatch) ends the session with the host's reason", () => {
 		const client = new GuestClient(LINK, "tester");
 		client.applyFrameForTest({