diff --git a/src/core/services/ipc.test.ts b/src/core/services/ipc.test.ts
index 6806f32..e7013bf 100644
--- a/src/core/services/ipc.test.ts
+++ b/src/core/services/ipc.test.ts
@@ -439,6 +439,51 @@ test('registerIpcHandlers validates and clamps stats request limits', async () =
   ]);
 });
 
+test('registerIpcHandlers requests the full timeline when no limit is provided', async () => {
+  const { registrar, handlers } = createFakeIpcRegistrar();
+  const calls: Array<[string, number | undefined, number]> = [];
+
+  registerIpcHandlers(
+    createRegisterIpcDeps({
+      immersionTracker: {
+        recordYomitanLookup: () => {},
+        getSessionSummaries: async () => [],
+        getDailyRollups: async () => [],
+        getMonthlyRollups: async () => [],
+        getQueryHints: async () => ({
+          totalSessions: 0,
+          activeSessions: 0,
+          episodesToday: 0,
+          activeAnimeCount: 0,
+          totalCards: 0,
+          totalActiveMin: 0,
+          activeDays: 0,
+          totalEpisodesWatched: 0,
+          totalAnimeCompleted: 0,
+        }),
+        getSessionTimeline: async (sessionId: number, limit?: number) => {
+          calls.push(['timeline', limit, sessionId]);
+          return [];
+        },
+        getSessionEvents: async () => [],
+        getVocabularyStats: async () => [],
+        getKanjiStats: async () => [],
+        getMediaLibrary: async () => [],
+        getMediaDetail: async () => null,
+        getMediaSessions: async () => [],
+        getMediaDailyRollups: async () => [],
+        getCoverArt: async () => null,
+        markActiveVideoWatched: async () => false,
+      },
+    }),
+    registrar,
+  );
+
+  await handlers.handle.get(IPC_CHANNELS.request.statsGetSessionTimeline)!({}, 7, undefined);
+
+  assert.deepEqual(calls, [['timeline', undefined, 7]]);
+});
+
 test('registerIpcHandlers ignores malformed fire-and-forget payloads', () => {
   const { registrar, handlers } = createFakeIpcRegistrar();
   const saves: unknown[] = [];
diff --git a/src/core/services/ipc.ts b/src/core/services/ipc.ts
index 8fca6be..cc7749d 100644
--- a/src/core/services/ipc.ts
+++ b/src/core/services/ipc.ts
@@ -517,7 +517,7 @@ export function registerIpcHandlers(deps: IpcServiceDeps, ipc: IpcMainRegistrar
     async (_event, sessionId: unknown, limit: unknown) => {
       const parsedSessionId = parsePositiveInteger(sessionId);
       if (parsedSessionId === null) return [];
-      const parsedLimit = parsePositiveIntLimit(limit, 200, 1000);
+      const parsedLimit = limit === undefined ? undefined : parsePositiveIntLimit(limit, 200, 1000);
       return deps.immersionTracker?.getSessionTimeline(parsedSessionId, parsedLimit) ?? [];
     },
   );
diff --git a/src/core/services/stats-server.ts b/src/core/services/stats-server.ts
index c458e39..3d88b01 100644
--- a/src/core/services/stats-server.ts
+++ b/src/core/services/stats-server.ts
@@ -189,7 +189,8 @@ export function createStatsApp(
   app.get('/api/stats/sessions/:id/timeline', async (c) => {
     const id = parseIntQuery(c.req.param('id'), 0);
     if (id <= 0) return c.json([], 400);
-    const limit = parseIntQuery(c.req.query('limit'), 200, 1000);
+    const rawLimit = c.req.query('limit');
+    const limit = rawLimit === undefined ? undefined : parseIntQuery(rawLimit, 200, 1000);
     const timeline = await tracker.getSessionTimeline(id, limit);
     return c.json(timeline);
   });
diff --git a/stats/src/lib/api-client.ts b/stats/src/lib/api-client.ts
index 1e0685f..1919022 100644
--- a/stats/src/lib/api-client.ts
+++ b/stats/src/lib/api-client.ts
@@ -70,8 +70,12 @@ export const apiClient = {
   getMonthlyRollups: (limit = 24) =>
     fetchJson<MonthlyRollup[]>(`/api/stats/monthly-rollups?limit=${limit}`),
   getSessions: (limit = 50) => fetchJson<SessionSummary[]>(`/api/stats/sessions?limit=${limit}`),
-  getSessionTimeline: (id: number, limit = 200) =>
-    fetchJson<SessionTimelinePoint[]>(`/api/stats/sessions/${id}/timeline?limit=${limit}`),
+  getSessionTimeline: (id: number, limit?: number) =>
+    fetchJson<SessionTimelinePoint[]>(
+      limit === undefined
+        ? `/api/stats/sessions/${id}/timeline`
+        : `/api/stats/sessions/${id}/timeline?limit=${limit}`,
+    ),
   getSessionEvents: (id: number, limit = 500) =>
     fetchJson<SessionEvent[]>(`/api/stats/sessions/${id}/events?limit=${limit}`),
   getSessionKnownWordsTimeline: (id: number) =>
diff --git a/stats/src/lib/ipc-client.ts b/stats/src/lib/ipc-client.ts
index 083411a..bc46df7 100644
--- a/stats/src/lib/ipc-client.ts
+++ b/stats/src/lib/ipc-client.ts
@@ -83,7 +83,7 @@ export const ipcClient = {
   getDailyRollups: (limit = 60) => getIpc().getDailyRollups(limit),
   getMonthlyRollups: (limit = 24) => getIpc().getMonthlyRollups(limit),
   getSessions: (limit = 50) => getIpc().getSessions(limit),
-  getSessionTimeline: (id: number, limit = 200) => getIpc().getSessionTimeline(id, limit),
+  getSessionTimeline: (id: number, limit?: number) => getIpc().getSessionTimeline(id, limit),
   getSessionEvents: (id: number, limit = 500) => getIpc().getSessionEvents(id, limit),
   getVocabulary: (limit = 100) => getIpc().getVocabulary(limit),
   getWordOccurrences: (headword: string, word: string, reading: string, limit = 50, offset = 0) =>