fix(chat): recover from an expired session instead of dead-ending on it

src/lib/session-title.test.ts

@@ -88,3 +88,32 @@ describe("mayReplaceTitle", () => {
     expect(mayReplaceTitle("Matty comp", "Fix the table layout")).toBe(false);
   });
 });
+
+describe("sanitizeGeneratedTitle — auth-expiry guard", () => {
+  it("rejects the exact string that branded a session in v0.6.0", () => {
+    // Passes every other filter: 1 line, 72 chars, 11 words - which is how it
+    // became the permanent title "Failed to authenticate: OAuth session ...".
+    expect(
+      sanitizeGeneratedTitle(
+        "Failed to authenticate: OAuth session expired and could not be refreshed",
+      ),
+    ).toBeNull();
+  });
+
+  it("rejects other vendor auth-failure phrasings", () => {
+    expect(sanitizeGeneratedTitle("Session expired")).toBeNull();
+    expect(sanitizeGeneratedTitle("invalid_grant")).toBeNull();
+    expect(sanitizeGeneratedTitle("not_authenticated")).toBeNull();
+  });
+
+  it("keeps titles that merely mention auth", () => {
+    // The strict matcher exists for exactly these: real work about auth must
+    // still get a real name.
+    expect(sanitizeGeneratedTitle("Fixing the unauthorized API error")).toBe(
+      "Fixing the unauthorized API error",
+    );
+    expect(sanitizeGeneratedTitle("Add OAuth login to the desktop app")).toBe(
+      "Add OAuth login to the desktop app",
+    );
+  });
+});

src/lib/session-title.ts

@@ -8,6 +8,8 @@
  * generated title takes over once the first exchange is done.
  */
 
+import { isAuthExpiryText } from "$lib/utils/auth-errors";
+
 /** Tabs truncate around here; longer titles only add ellipsis. */
 export const MAX_TITLE_LENGTH = 60;
 
@@ -51,6 +53,14 @@ export function cleanPromptTitle(prompt: string): string {
 export function sanitizeGeneratedTitle(raw: string): string | null {
   let text = String(raw ?? "").trim();
   if (!text) return null;
+  // The title comes from a throwaway CLI run. When that run fails on expired
+  // auth it returns the failure text, which passes every check below - one
+  // line, 72 chars, 11 words - so the session gets permanently named
+  // "Failed to authenticate: OAuth session expired and could not". A transient
+  // auth blip must not brand a session forever; drop it and keep the
+  // prompt-derived title. Strict matcher: a title that merely mentions auth
+  // (say "Fixing the unauthorized API error") is a legitimate name.
+  if (isAuthExpiryText(text)) return null;
   // Unwrap a fenced block before counting lines — the fence is the model's formatting, not
   // part of the answer, and its newlines would otherwise look like an essay.
   const fenced = text.match(/^```[a-z]*\s*\n?([\s\S]*?)\n?\s*```$/i);

src/lib/utils/auth-errors.ts

@@ -27,3 +27,31 @@ export function isAuthExpiryError(text: string | null | undefined): boolean {
   const t = String(text).toLowerCase();
   return AUTH_EXPIRY_MARKERS.some((m) => t.includes(m));
 }
+
+/** Phrasings the vendor CLIs actually emit when their own OAuth failed. Unlike
+ *  AUTH_EXPIRY_MARKERS this must not match text that merely *discusses* auth:
+ *  bare "authenticate" / "unauthorized" are deliberately absent, because a
+ *  legitimate chat about a 401 would otherwise be mistaken for a failure.
+ *
+ *  Still not airtight, and it does not need to be: "session expired" would also
+ *  reject a title like "Session expired handling in Redis". The cost of a false
+ *  positive here is bounded - the session keeps its prompt-derived name - so the
+ *  list is tuned to never MISS a real failure, and to miss as few good titles as
+ *  it reasonably can. */
+const AUTH_EXPIRY_STRICT_MARKERS = [
+  "oauth session expired",
+  "could not be refreshed",
+  "failed to authenticate",
+  "session expired",
+  "not_authenticated",
+  "invalid_grant",
+];
+
+/** Strict variant of {@link isAuthExpiryError}, for places where the text may be
+ *  ordinary content rather than a raw error — e.g. a model-generated session
+ *  title, where a false positive silently discards a good title. */
+export function isAuthExpiryText(text: string | null | undefined): boolean {
+  if (!text) return false;
+  const t = String(text).toLowerCase();
+  return AUTH_EXPIRY_STRICT_MARKERS.some((m) => t.includes(m));
+}