diff --git a/src/lib/twitter-client-timelines.ts b/src/lib/twitter-client-timelines.ts
index f81ed47..acf4d1c 100644
--- a/src/lib/twitter-client-timelines.ts
+++ b/src/lib/twitter-client-timelines.ts
@@ -541,7 +541,7 @@ export function withTimelines<TBase extends AbstractConstructor<TwitterClientBas
         });
 
         // Retry-After supports delta-seconds only; HTTP-date falls back to backoff.
-        const retryAfter = response.headers.get('retry-after');
+        const retryAfter = response.headers?.get?.('retry-after');
         const retryAfterMs = retryAfter ? Number.parseInt(retryAfter, 10) * 1000 : Number.NaN;
         const backoffMs = Number.isFinite(retryAfterMs)
           ? retryAfterMs
diff --git a/tests/commands.bookmarks.test.ts b/tests/commands.bookmarks.test.ts
index 2fe72b8..2d67487 100644
--- a/tests/commands.bookmarks.test.ts
+++ b/tests/commands.bookmarks.test.ts
@@ -17,12 +17,6 @@ describe('bookmarks command', () => {
     } as unknown as CliContext;
 
     registerBookmarksCommand(program, ctx);
-    const command = program.commands.find((cmd) => cmd.name() === 'bookmarks');
-    if (!command) {
-      throw new Error('bookmarks command not registered');
-    }
-
-    const action = (command as { _actionHandler: (opts: Record<string, string>) => Promise<void> })._actionHandler;
     const exitSpy = vi
       .spyOn(process, 'exit')
       .mockImplementation(((code?: number) => {
@@ -31,7 +25,7 @@ describe('bookmarks command', () => {
     const errorSpy = vi.spyOn(console, 'error').mockImplementation(() => undefined);
 
     try {
-      await expect(action({ maxPages: '2' })).rejects.toThrow('exit 1');
+      await expect(program.parseAsync(['node', 'bird', 'bookmarks', '--max-pages', '2'])).rejects.toThrow('exit 1');
       expect(errorSpy).toHaveBeenCalledWith(expect.stringContaining('--max-pages requires --all'));
     } finally {
       exitSpy.mockRestore();
diff --git a/tests/twitter-client-coverage.api.test.ts b/tests/twitter-client-coverage.api.test.ts
index 3e059c1..503b7f6 100644
--- a/tests/twitter-client-coverage.api.test.ts
+++ b/tests/twitter-client-coverage.api.test.ts
@@ -155,10 +155,14 @@ describe('TwitterClient API coverage', () => {
     it('returns an error for non-ok responses', async () => {
       const mockFetch = vi
         .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'down' }))
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'down' }))
         .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'down' }));
       global.fetch = mockFetch as unknown as typeof fetch;
 
       const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientApiPrivate;
+      clientPrivate.getBookmarksQueryIds = async () => ['test'];
       const result = await client.getBookmarks(1);
 
       expect(result.success).toBe(false);
@@ -174,6 +178,8 @@ describe('TwitterClient API coverage', () => {
       global.fetch = mockFetch as unknown as typeof fetch;
 
       const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientApiPrivate;
+      clientPrivate.getBookmarksQueryIds = async () => ['test'];
       const result = await client.getBookmarks(1);
 
       expect(result.success).toBe(false);
@@ -185,6 +191,8 @@ describe('TwitterClient API coverage', () => {
       global.fetch = mockFetch as unknown as typeof fetch;
 
       const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientApiPrivate;
+      clientPrivate.getBookmarksQueryIds = async () => ['test'];
       const result = await client.getBookmarks(1);
 
       expect(result.success).toBe(false);
@@ -362,10 +370,14 @@ describe('TwitterClient API coverage', () => {
     it('returns an error for non-ok responses', async () => {
       const mockFetch = vi
         .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'down' }))
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'down' }))
         .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'down' }));
       global.fetch = mockFetch as unknown as typeof fetch;
 
       const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientApiPrivate;
+      clientPrivate.getBookmarkFolderQueryIds = async () => ['test'];
       const result = await client.getBookmarkFolderTimeline('123', 1);
 
       expect(result.success).toBe(false);
@@ -381,6 +393,8 @@ describe('TwitterClient API coverage', () => {
       global.fetch = mockFetch as unknown as typeof fetch;
 
       const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientApiPrivate;
+      clientPrivate.getBookmarkFolderQueryIds = async () => ['test'];
       const result = await client.getBookmarkFolderTimeline('123', 1);
 
       expect(result.success).toBe(false);
@@ -392,6 +406,8 @@ describe('TwitterClient API coverage', () => {
       global.fetch = mockFetch as unknown as typeof fetch;
 
       const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientApiPrivate;
+      clientPrivate.getBookmarkFolderQueryIds = async () => ['test'];
       const result = await client.getBookmarkFolderTimeline('123', 1);
 
       expect(result.success).toBe(false);