fix: follow the decreasing event sync cursor and never return partial lists

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- `get_events` and `list_memos` now read every event in large calendars. The events sync endpoint returns the newest chunk first with a decreasing cursor, and paging stopped after the first chunk. Paging now continues while the cursor is new, in either direction.
+- Event paging fails with an error instead of returning a partial list when the cursor repeats or no last chunk arrives within 200 pages, and keeps one entry per event when chunks overlap.
+
 ## [0.5.0] - 2026-10-07
 
 ### Added

src/client/api.ts

@@ -75,6 +75,9 @@ function getErrorMessage(error: unknown): string {
   return error instanceof Error ? error.message : String(error);
 }
 
+/** Upper bound for event paging; at about 300 events per chunk far above real calendars. */
+const MAX_EVENT_PAGES = 200;
+
 function todayUtcMidnight(): number {
   const now = new Date();
   return Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate());
@@ -292,28 +295,47 @@ export class TimeTreeAPIClient {
   /**
    * Fetch every page of an event feed. TimeTree splits large responses into chunks: while
    * `chunk` is true, the returned `since` is the cursor for the next page.
+   *
+   * The cursor does not always grow: the events sync endpoint returns the newest chunk
+   * first and reports the oldest `updated_at` of that chunk, so its cursor decreases.
+   * Paging therefore continues while the cursor is new, in either direction. A repeated
+   * cursor or too many pages is an error, never a silently truncated list: callers that
+   * compare listings would read the missing events as deleted.
    */
   private async fetchEventPages(
     buildUrl: (since: number) => string,
     since: number
   ): Promise<Event[]> {
-    const events: Event[] = [];
+    // Chunks can overlap at their boundary; keep the newest version per uuid.
+    const byUuid = new Map<string, Event>();
+    const visited = new Set<number>([since]);
     let cursor = since;
 
-    for (;;) {
+    for (let page = 1; page <= MAX_EVENT_PAGES; page++) {
       const response = await this.send(async () => {
         return await this.authManager.getHttpClient().get<EventsSyncResponse>(buildUrl(cursor));
       });
 
       const validated = EventsSyncResponseSchema.parse(response);
-      events.push(...validated.events);
+      for (const event of validated.events) {
+        const known = byUuid.get(event.uuid);
+        if (!known || (event.updated_at ?? 0) >= (known.updated_at ?? 0)) {
+          byUuid.set(event.uuid, event);
+        }
+      }
 
-      if (!validated.chunk || validated.since <= cursor) {
-        return events;
+      if (!validated.chunk) {
+        return [...byUuid.values()];
+      }
+      if (visited.has(validated.since)) {
+        throw new TimeTreeAPIError(`Event paging stopped: cursor ${validated.since} repeated before the last chunk`);
       }
-      logger.debug('More events to fetch', { nextSince: validated.since, fetchedSoFar: events.length });
+      logger.debug('More events to fetch', { nextSince: validated.since, fetchedSoFar: byUuid.size });
+      visited.add(validated.since);
       cursor = validated.since;
     }
+
+    throw new TimeTreeAPIError(`Event paging stopped: no last chunk after ${MAX_EVENT_PAGES} pages`);
   }
 
   /** Sync all active events from a calendar with automatic pagination. */

tests/regressions.test.mjs

@@ -361,3 +361,66 @@ test('sign-in goes through the rate limiter', async () => {
   await client.getCalendars();
   assert.equal(limited, 2, 'expected one limited call for sign-in and one for the request');
 });
+
+function pagedClient(pages) {
+  const cursors = [];
+  const client = makeClient({
+    get: async (url) => {
+      const since = Number(new URL(url).searchParams.get('since'));
+      cursors.push(since);
+      const page = pages[since];
+      if (!page) throw new Error(`unexpected since=${since}`);
+      return page;
+    },
+  });
+  return { client, cursors };
+}
+
+test('event sync follows a decreasing cursor (newest chunk first)', async () => {
+  const { client, cursors } = pagedClient({
+    0: { chunk: true, since: 800, events: [makeEvent({ uuid: 'a', updated_at: 900 }), makeEvent({ uuid: 'b', updated_at: 800 })] },
+    800: { chunk: true, since: 600, events: [makeEvent({ uuid: 'c', updated_at: 700 }), makeEvent({ uuid: 'd', updated_at: 600 })] },
+    600: { chunk: false, since: 500, events: [makeEvent({ uuid: 'e', updated_at: 500 })] },
+  });
+
+  const events = await client.getEventsByCalendar('123');
+
+  assert.deepEqual(cursors, [0, 800, 600]);
+  assert.deepEqual(events.map((event) => event.uuid), ['a', 'b', 'c', 'd', 'e']);
+});
+
+test('event paging keeps one entry per uuid when chunks overlap', async () => {
+  const { client } = pagedClient({
+    0: { chunk: true, since: 800, events: [makeEvent({ uuid: 'a', updated_at: 900 }), makeEvent({ uuid: 'b', updated_at: 800 })] },
+    800: { chunk: false, since: 700, events: [makeEvent({ uuid: 'b', updated_at: 800 }), makeEvent({ uuid: 'c', updated_at: 700 })] },
+  });
+
+  const events = await client.getEventsByCalendar('123');
+
+  assert.deepEqual(events.map((event) => event.uuid), ['a', 'b', 'c']);
+});
+
+test('event paging fails instead of returning a partial list when the cursor repeats', async () => {
+  const { client, cursors } = pagedClient({
+    0: { chunk: true, since: 800, events: [makeEvent({ uuid: 'a', updated_at: 900 })] },
+    800: { chunk: true, since: 700, events: [makeEvent({ uuid: 'b', updated_at: 800 })] },
+    700: { chunk: true, since: 800, events: [makeEvent({ uuid: 'c', updated_at: 700 })] },
+  });
+
+  await assert.rejects(client.getEventsByCalendar('123'), /cursor 800 repeated/);
+  assert.deepEqual(cursors, [0, 800, 700]);
+});
+
+test('event paging fails instead of returning a partial list after the page limit', async () => {
+  let calls = 0;
+  const client = makeClient({
+    get: async (url) => {
+      calls += 1;
+      const since = Number(new URL(url).searchParams.get('since'));
+      return { chunk: true, since: since + 1, events: [makeEvent({ uuid: `e${since}` })] };
+    },
+  });
+
+  await assert.rejects(client.getEventsByCalendar('123'), /no last chunk after 200 pages/);
+  assert.equal(calls, 200);
+});