diff --git a/biome.json b/biome.json
index 5139e91..e2ada81 100644
--- a/biome.json
+++ b/biome.json
@@ -11,10 +11,28 @@
     "rules": {
       "recommended": true,
       "complexity": {
-        "noForEach": "off"
+        "noForEach": "error"
+      },
+      "correctness": {
+        "useImportExtensions": {
+          "level": "error",
+          "options": {
+            "forceJsExtensions": true
+          }
+        }
+      },
+      "performance": {
+        "useTopLevelRegex": "error"
       },
       "style": {
-        "noNonNullAssertion": "off"
+        "noNonNullAssertion": "error",
+        "useBlockStatements": "error"
+      },
+      "suspicious": {
+        "noExplicitAny": "error"
+      },
+      "nursery": {
+        "useRegexpExec": "error"
       }
     }
   },
diff --git a/src/index.ts b/src/index.ts
index 931064a..7c4a9e6 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -32,16 +32,19 @@ import { runtimeQueryIds } from './lib/runtime-query-ids.js';
 import { type TweetData, TwitterClient } from './lib/twitter-client.js';
 import { getCliVersion } from './lib/version.js';
 
-const program = new Command();
+const program: Command = new Command();
 
-const rawArgs = process.argv.slice(2);
-const normalizedArgs = rawArgs[0] === '--' ? rawArgs.slice(1) : rawArgs;
-const isTty = process.stdout.isTTY;
+const rawArgs: string[] = process.argv.slice(2);
+const normalizedArgs: string[] = rawArgs[0] === '--' ? rawArgs.slice(1) : rawArgs;
+const isTty: boolean = process.stdout.isTTY;
 let output: OutputConfig = resolveOutputConfigFromArgv(normalizedArgs, process.env, isTty);
 kleur.enabled = output.color;
 
-const wrap = (styler: (text: string) => string) => (text: string) => (isTty ? styler(text) : text);
-const collect = (value: string, previous: string[] = []) => {
+const wrap =
+  (styler: (text: string) => string): ((text: string) => string) =>
+  (text: string): string =>
+    isTty ? styler(text) : text;
+const collect = (value: string, previous: string[] = []): string[] => {
   previous.push(value);
   return previous;
 };
@@ -50,16 +53,22 @@ const COOKIE_SOURCES: CookieSource[] = ['safari', 'chrome', 'firefox'];
 
 function parseCookieSource(value: string): CookieSource {
   const normalized = value.trim().toLowerCase();
-  if (normalized === 'safari' || normalized === 'chrome' || normalized === 'firefox') return normalized;
+  if (normalized === 'safari' || normalized === 'chrome' || normalized === 'firefox') {
+    return normalized;
+  }
   throw new Error(`Invalid --cookie-source "${value}". Allowed: safari, chrome, firefox.`);
 }
 
 function resolveCookieSourceOrder(input: unknown): CookieSource[] | undefined {
-  if (typeof input === 'string') return [parseCookieSource(input)];
+  if (typeof input === 'string') {
+    return [parseCookieSource(input)];
+  }
   if (Array.isArray(input)) {
     const result: CookieSource[] = [];
     for (const entry of input) {
-      if (typeof entry !== 'string') continue;
+      if (typeof entry !== 'string') {
+        continue;
+      }
       result.push(parseCookieSource(entry));
     }
     return result.length > 0 ? result : undefined;
@@ -67,15 +76,15 @@ function resolveCookieSourceOrder(input: unknown): CookieSource[] | undefined {
   return undefined;
 }
 
-const collectCookieSource = (value: string, previous: CookieSource[] = []) => {
+const collectCookieSource = (value: string, previous: CookieSource[] = []): CookieSource[] => {
   previous.push(parseCookieSource(value));
   return previous;
 };
 
-const p = (kind: Parameters<typeof statusPrefix>[0]) => statusPrefix(kind, output);
-const l = (kind: Parameters<typeof labelPrefix>[0]) => labelPrefix(kind, output);
+const p = (kind: Parameters<typeof statusPrefix>[0]): string => statusPrefix(kind, output);
+const l = (kind: Parameters<typeof labelPrefix>[0]): string => labelPrefix(kind, output);
 
-function applyOutputFromCommand(command: Command) {
+function applyOutputFromCommand(command: Command): void {
   const opts = command.optsWithGlobals() as { plain?: boolean; emoji?: boolean; color?: boolean };
   output = resolveOutputConfigFromCommander(opts, process.env, isTty);
   kleur.enabled = output.color;
@@ -102,7 +111,9 @@ type BirdConfig = {
 };
 
 function readConfigFile(path: string): Partial<BirdConfig> {
-  if (!existsSync(path)) return {};
+  if (!existsSync(path)) {
+    return {};
+  }
   try {
     const raw = readFileSync(path, 'utf8');
     const parsed = JSON5.parse(raw) as Partial<BirdConfig>;
@@ -151,7 +162,7 @@ program.addHelpText(
 
 program.name('bird').description('Post tweets and replies via Twitter/X GraphQL API').version(getCliVersion());
 
-const formatExample = (command: string, description: string) =>
+const formatExample = (command: string, description: string): string =>
   `${colors.command(`  ${command}`)}\n${colors.muted(`    ${description}`)}`;
 
 program.addHelpText(
@@ -192,7 +203,7 @@ type CredentialsOptions = {
   cookieSource?: CookieSource[];
 };
 
-function resolveCredentialsFromOptions(opts: CredentialsOptions) {
+function resolveCredentialsFromOptions(opts: CredentialsOptions): ReturnType<typeof resolveCredentials> {
   const cookieSource = opts.cookieSource?.length
     ? opts.cookieSource
     : (resolveCookieSourceOrder(config.cookieSource) ?? COOKIE_SOURCES);
@@ -213,9 +224,13 @@ type MediaSpec = { path: string; alt?: string; mime: string; buffer: Buffer };
 
 function resolveTimeoutMs(...values: Array<string | number | undefined | null>): number | undefined {
   for (const value of values) {
-    if (value === undefined || value === null || value === '') continue;
+    if (value === undefined || value === null || value === '') {
+      continue;
+    }
     const parsed = typeof value === 'number' ? value : Number(value);
-    if (Number.isFinite(parsed) && parsed > 0) return parsed;
+    if (Number.isFinite(parsed) && parsed > 0) {
+      return parsed;
+    }
   }
   return undefined;
 }
@@ -226,17 +241,31 @@ function resolveTimeoutFromOptions(options: { timeout?: string | number }): numb
 
 function detectMime(path: string): string | null {
   const ext = path.toLowerCase();
-  if (ext.endsWith('.jpg') || ext.endsWith('.jpeg')) return 'image/jpeg';
-  if (ext.endsWith('.png')) return 'image/png';
-  if (ext.endsWith('.webp')) return 'image/webp';
-  if (ext.endsWith('.gif')) return 'image/gif';
-  if (ext.endsWith('.mp4') || ext.endsWith('.m4v')) return 'video/mp4';
-  if (ext.endsWith('.mov')) return 'video/quicktime';
+  if (ext.endsWith('.jpg') || ext.endsWith('.jpeg')) {
+    return 'image/jpeg';
+  }
+  if (ext.endsWith('.png')) {
+    return 'image/png';
+  }
+  if (ext.endsWith('.webp')) {
+    return 'image/webp';
+  }
+  if (ext.endsWith('.gif')) {
+    return 'image/gif';
+  }
+  if (ext.endsWith('.mp4') || ext.endsWith('.m4v')) {
+    return 'video/mp4';
+  }
+  if (ext.endsWith('.mov')) {
+    return 'video/quicktime';
+  }
   return null;
 }
 
 function loadMedia(opts: { media: string[]; alts: string[] }): MediaSpec[] {
-  if (opts.media.length === 0) return [];
+  if (opts.media.length === 0) {
+    return [];
+  }
   const specs: MediaSpec[] = [];
   for (const [index, path] of opts.media.entries()) {
     const mime = detectMime(path);
@@ -248,9 +277,15 @@ function loadMedia(opts: { media: string[]; alts: string[] }): MediaSpec[] {
   }
 
   const videoCount = specs.filter((m) => m.mime.startsWith('video/')).length;
-  if (videoCount > 1) throw new Error('Only one video can be attached');
-  if (videoCount === 1 && specs.length > 1) throw new Error('Video cannot be combined with other media');
-  if (specs.length > 4) throw new Error('Maximum 4 media attachments');
+  if (videoCount > 1) {
+    throw new Error('Only one video can be attached');
+  }
+  if (videoCount === 1 && specs.length > 1) {
+    throw new Error('Video cannot be combined with other media');
+  }
+  if (specs.length > 4) {
+    throw new Error('Maximum 4 media attachments');
+  }
   return specs;
 }
 
diff --git a/src/lib/cli-args.ts b/src/lib/cli-args.ts
index 1b7c8ef..6e1c2c4 100644
--- a/src/lib/cli-args.ts
+++ b/src/lib/cli-args.ts
@@ -8,7 +8,9 @@ const TWEET_ID_REGEX = /^\d{8,}$/;
 
 export function looksLikeTweetInput(value: string): boolean {
   const trimmed = value.trim();
-  if (!trimmed) return false;
+  if (!trimmed) {
+    return false;
+  }
   return TWEET_URL_REGEX.test(trimmed) || TWEET_ID_REGEX.test(trimmed);
 }
 
diff --git a/src/lib/cookies.ts b/src/lib/cookies.ts
index 4c0556a..9df0825 100644
--- a/src/lib/cookies.ts
+++ b/src/lib/cookies.ts
@@ -21,10 +21,12 @@ export type CookieSource = 'safari' | 'chrome' | 'firefox';
 
 const TWITTER_COOKIE_NAMES = ['auth_token', 'ct0'] as const;
 const TWITTER_URL = 'https://x.com/';
-const TWITTER_ORIGINS = ['https://x.com/', 'https://twitter.com/'];
+const TWITTER_ORIGINS: string[] = ['https://x.com/', 'https://twitter.com/'];
 
 function normalizeValue(value: unknown): string | null {
-  if (typeof value !== 'string') return null;
+  if (typeof value !== 'string') {
+    return null;
+  }
   const trimmed = value.trim();
   return trimmed.length > 0 ? trimmed : null;
 }
@@ -38,24 +40,36 @@ function buildEmpty(): TwitterCookies {
 }
 
 function readEnvCookie(cookies: TwitterCookies, keys: readonly string[], field: 'authToken' | 'ct0'): void {
-  if (cookies[field]) return;
+  if (cookies[field]) {
+    return;
+  }
   for (const key of keys) {
     const value = normalizeValue(process.env[key]);
-    if (!value) continue;
+    if (!value) {
+      continue;
+    }
     cookies[field] = value;
-    if (!cookies.source) cookies.source = `env ${key}`;
+    if (!cookies.source) {
+      cookies.source = `env ${key}`;
+    }
     break;
   }
 }
 
 function resolveSources(cookieSource?: CookieSource | CookieSource[]): CookieSource[] {
-  if (Array.isArray(cookieSource)) return cookieSource;
-  if (cookieSource) return [cookieSource];
+  if (Array.isArray(cookieSource)) {
+    return cookieSource;
+  }
+  if (cookieSource) {
+    return [cookieSource];
+  }
   return ['safari', 'chrome', 'firefox'];
 }
 
 function labelForSource(source: CookieSource, profile?: string): string {
-  if (source === 'safari') return 'Safari';
+  if (source === 'safari') {
+    return 'Safari';
+  }
   if (source === 'chrome') {
     return profile ? `Chrome profile "${profile}"` : 'Chrome default profile';
   }
@@ -67,13 +81,19 @@ function pickCookieValue(
   name: (typeof TWITTER_COOKIE_NAMES)[number],
 ): string | null {
   const matches = cookies.filter((c) => c?.name === name && typeof c.value === 'string');
-  if (matches.length === 0) return null;
+  if (matches.length === 0) {
+    return null;
+  }
 
   const preferred = matches.find((c) => (c.domain ?? '').endsWith('x.com'));
-  if (preferred?.value) return preferred.value;
+  if (preferred?.value) {
+    return preferred.value;
+  }
 
   const twitter = matches.find((c) => (c.domain ?? '').endsWith('twitter.com'));
-  if (twitter?.value) return twitter.value;
+  if (twitter?.value) {
+    return twitter.value;
+  }
 
   return matches[0]?.value ?? null;
 }
@@ -99,8 +119,12 @@ async function readTwitterCookiesFromBrowser(options: {
 
   const authToken = pickCookieValue(cookies, 'auth_token');
   const ct0 = pickCookieValue(cookies, 'ct0');
-  if (authToken) out.authToken = authToken;
-  if (ct0) out.ct0 = ct0;
+  if (authToken) {
+    out.authToken = authToken;
+  }
+  if (ct0) {
+    out.ct0 = ct0;
+  }
 
   if (out.authToken && out.ct0) {
     out.cookieHeader = cookieHeader(out.authToken, out.ct0);
@@ -156,7 +180,9 @@ export async function resolveCredentials(options: {
   }
   if (options.ct0) {
     cookies.ct0 = options.ct0;
-    if (!cookies.source) cookies.source = 'CLI argument';
+    if (!cookies.source) {
+      cookies.source = 'CLI argument';
+    }
   }
 
   readEnvCookie(cookies, ['AUTH_TOKEN', 'TWITTER_AUTH_TOKEN'], 'authToken');
diff --git a/src/lib/extract-tweet-id.ts b/src/lib/extract-tweet-id.ts
index f8df6f6..ae46b93 100644
--- a/src/lib/extract-tweet-id.ts
+++ b/src/lib/extract-tweet-id.ts
@@ -1,9 +1,11 @@
 /**
  * Extract tweet ID from a Twitter/X URL or return the input unchanged if it's already an ID.
  */
+const TWEET_URL_REGEX = /(?:twitter\.com|x\.com)\/\w+\/status\/(\d+)/;
+
 export function extractTweetId(input: string): string {
   // If it's a URL, extract the tweet ID
-  const urlMatch = input.match(/(?:twitter\.com|x\.com)\/\w+\/status\/(\d+)/);
+  const urlMatch = TWEET_URL_REGEX.exec(input);
   if (urlMatch) {
     return urlMatch[1];
   }
diff --git a/src/lib/normalize-handle.ts b/src/lib/normalize-handle.ts
index 2d6572e..127dc0d 100644
--- a/src/lib/normalize-handle.ts
+++ b/src/lib/normalize-handle.ts
@@ -1,13 +1,21 @@
+const HANDLE_REGEX = /^[A-Za-z0-9_]{1,15}$/;
+
 export function normalizeHandle(input?: string | null): string | null {
   const raw = (input ?? '').trim();
-  if (!raw) return null;
+  if (!raw) {
+    return null;
+  }
 
   const withoutAt = raw.startsWith('@') ? raw.slice(1) : raw;
   const handle = withoutAt.trim();
-  if (!handle) return null;
+  if (!handle) {
+    return null;
+  }
 
   // X/Twitter handles are traditionally max 15 chars; keep strict to avoid surprising queries.
-  if (!/^[A-Za-z0-9_]{1,15}$/.test(handle)) return null;
+  if (!HANDLE_REGEX.test(handle)) {
+    return null;
+  }
 
   return handle;
 }
@@ -16,7 +24,9 @@ export function mentionsQueryFromUserOption(userOption?: string | null): {
   query: string | null;
   error: string | null;
 } {
-  if (typeof userOption === 'undefined') return { query: null, error: null };
+  if (typeof userOption === 'undefined') {
+    return { query: null, error: null };
+  }
 
   const handle = normalizeHandle(userOption);
   if (!handle) {
diff --git a/src/lib/output.ts b/src/lib/output.ts
index 61aeece..8ed1bff 100644
--- a/src/lib/output.ts
+++ b/src/lib/output.ts
@@ -53,14 +53,22 @@ export function resolveOutputConfigFromCommander(
 }
 
 export function statusPrefix(kind: StatusKind, cfg: OutputConfig): string {
-  if (cfg.plain) return `${STATUS[kind].plain} `;
-  if (cfg.emoji) return `${STATUS[kind].emoji} `;
+  if (cfg.plain) {
+    return `${STATUS[kind].plain} `;
+  }
+  if (cfg.emoji) {
+    return `${STATUS[kind].emoji} `;
+  }
   return `${STATUS[kind].text} `;
 }
 
 export function labelPrefix(kind: LabelKind, cfg: OutputConfig): string {
-  if (cfg.plain) return `${LABELS[kind].plain} `;
-  if (cfg.emoji) return `${LABELS[kind].emoji} `;
+  if (cfg.plain) {
+    return `${LABELS[kind].plain} `;
+  }
+  if (cfg.emoji) {
+    return `${LABELS[kind].emoji} `;
+  }
   return `${LABELS[kind].text} `;
 }
 
@@ -72,8 +80,12 @@ export function formatStatsLine(
   const retweetCount = stats.retweetCount ?? 0;
   const replyCount = stats.replyCount ?? 0;
 
-  if (cfg.plain) return `likes: ${likeCount}  retweets: ${retweetCount}  replies: ${replyCount}`;
-  if (!cfg.emoji) return `Likes ${likeCount}  Retweets ${retweetCount}  Replies ${replyCount}`;
+  if (cfg.plain) {
+    return `likes: ${likeCount}  retweets: ${retweetCount}  replies: ${replyCount}`;
+  }
+  if (!cfg.emoji) {
+    return `Likes ${likeCount}  Retweets ${retweetCount}  Replies ${replyCount}`;
+  }
   return `❤️ ${likeCount}  🔁 ${retweetCount}  💬 ${replyCount}`;
 }
 
diff --git a/src/lib/runtime-query-ids.ts b/src/lib/runtime-query-ids.ts
index 9dfbf90..bd335b9 100644
--- a/src/lib/runtime-query-ids.ts
+++ b/src/lib/runtime-query-ids.ts
@@ -3,9 +3,9 @@ import { homedir } from 'node:os';
 import path from 'node:path';
 
 const DEFAULT_CACHE_FILENAME = 'query-ids-cache.json';
-const DEFAULT_TTL_MS = 24 * 60 * 60 * 1000;
+const DEFAULT_TTL_MS: number = 24 * 60 * 60 * 1000;
 
-const DISCOVERY_PAGES = [
+const DISCOVERY_PAGES: string[] = [
   'https://x.com/?lang=en',
   'https://x.com/explore',
   'https://x.com/notifications',
@@ -13,6 +13,7 @@ const DISCOVERY_PAGES = [
 ];
 
 const BUNDLE_URL_REGEX = /https:\/\/abs\.twimg\.com\/responsive-web\/client-web(?:-legacy)?\/[A-Za-z0-9.-]+\.js/g;
+const QUERY_ID_REGEX = /^[a-zA-Z0-9_-]+$/;
 
 const OPERATION_PATTERNS = [
   {
@@ -67,6 +68,15 @@ export type RuntimeQueryIdsOptions = {
   fetchImpl?: typeof fetch;
 };
 
+export type RuntimeQueryIdStore = {
+  cachePath: string;
+  ttlMs: number;
+  getSnapshotInfo: () => Promise<RuntimeQueryIdSnapshotInfo | null>;
+  getQueryId: (operationName: string) => Promise<string | null>;
+  refresh: (operationNames: string[], opts?: { force?: boolean }) => Promise<RuntimeQueryIdSnapshotInfo | null>;
+  clearMemory: () => void;
+};
+
 async function fetchText(fetchImpl: typeof fetch, url: string): Promise<string> {
   const response = await fetchImpl(url, { headers: HEADERS });
   if (!response.ok) {
@@ -85,7 +95,9 @@ function resolveDefaultCachePath(): string {
 }
 
 function parseSnapshot(raw: unknown): RuntimeQueryIdSnapshot | null {
-  if (!raw || typeof raw !== 'object') return null;
+  if (!raw || typeof raw !== 'object') {
+    return null;
+  }
   const record = raw as Record<string, unknown>;
   const fetchedAt = typeof record.fetchedAt === 'string' ? record.fetchedAt : null;
   const ttlMs = typeof record.ttlMs === 'number' && Number.isFinite(record.ttlMs) ? record.ttlMs : null;
@@ -93,10 +105,14 @@ function parseSnapshot(raw: unknown): RuntimeQueryIdSnapshot | null {
   const discovery =
     record.discovery && typeof record.discovery === 'object' ? (record.discovery as Record<string, unknown>) : null;
 
-  if (!fetchedAt || !ttlMs || !ids || !discovery) return null;
+  if (!fetchedAt || !ttlMs || !ids || !discovery) {
+    return null;
+  }
   const pages = Array.isArray(discovery.pages) ? discovery.pages : null;
   const bundles = Array.isArray(discovery.bundles) ? discovery.bundles : null;
-  if (!pages || !bundles) return null;
+  if (!pages || !bundles) {
+    return null;
+  }
 
   const normalizedIds: Record<string, string> = {};
   for (const [key, value] of Object.entries(ids)) {
@@ -122,7 +138,9 @@ async function readSnapshotFromDisk(cachePath: string): Promise<RuntimeQueryIdSn
     return parseSnapshot(JSON.parse(raw));
   } catch (error) {
     const code = error && typeof error === 'object' ? String((error as { code?: unknown }).code ?? '') : '';
-    if (code !== 'ENOENT') return null;
+    if (code !== 'ENOENT') {
+      return null;
+    }
     return null;
   }
 }
@@ -161,15 +179,27 @@ function extractOperations(
     pattern.regex.lastIndex = 0;
     while (true) {
       const match = pattern.regex.exec(bundleContents);
-      if (match === null) break;
+      if (match === null) {
+        break;
+      }
       const operationName = match[pattern.operationGroup];
       const queryId = match[pattern.queryIdGroup];
-      if (!operationName || !queryId) continue;
-      if (!targets.has(operationName)) continue;
-      if (!/^[a-zA-Z0-9_-]+$/.test(queryId)) continue;
-      if (discovered.has(operationName)) continue;
+      if (!operationName || !queryId) {
+        continue;
+      }
+      if (!targets.has(operationName)) {
+        continue;
+      }
+      if (!QUERY_ID_REGEX.test(queryId)) {
+        continue;
+      }
+      if (discovered.has(operationName)) {
+        continue;
+      }
       discovered.set(operationName, { queryId, bundle: bundleLabel });
-      if (discovered.size === targets.size) return;
+      if (discovered.size === targets.size) {
+        return;
+      }
     }
   }
 }
@@ -186,7 +216,9 @@ async function fetchAndExtract(
     const chunk = bundleUrls.slice(i, i + CONCURRENCY);
     await Promise.all(
       chunk.map(async (url) => {
-        if (discovered.size === targets.size) return;
+        if (discovered.size === targets.size) {
+          return;
+        }
         const label = url.split('/').at(-1) ?? url;
         try {
           const js = await fetchText(fetchImpl, url);
@@ -196,13 +228,15 @@ async function fetchAndExtract(
         }
       }),
     );
-    if (discovered.size === targets.size) break;
+    if (discovered.size === targets.size) {
+      break;
+    }
   }
 
   return discovered;
 }
 
-export function createRuntimeQueryIdStore(options: RuntimeQueryIdsOptions = {}) {
+export function createRuntimeQueryIdStore(options: RuntimeQueryIdsOptions = {}): RuntimeQueryIdStore {
   const fetchImpl = options.fetchImpl ?? fetch;
   const ttlMs = options.ttlMs ?? DEFAULT_TTL_MS;
   const cachePath = options.cachePath ? path.resolve(options.cachePath) : resolveDefaultCachePath();
@@ -212,7 +246,9 @@ export function createRuntimeQueryIdStore(options: RuntimeQueryIdsOptions = {})
   let refreshInFlight: Promise<RuntimeQueryIdSnapshotInfo | null> | null = null;
 
   const loadSnapshot = async (): Promise<RuntimeQueryIdSnapshot | null> => {
-    if (memorySnapshot) return memorySnapshot;
+    if (memorySnapshot) {
+      return memorySnapshot;
+    }
     if (!loadOnce) {
       loadOnce = (async () => {
         const fromDisk = await readSnapshotFromDisk(cachePath);
@@ -225,7 +261,9 @@ export function createRuntimeQueryIdStore(options: RuntimeQueryIdsOptions = {})
 
   const getSnapshotInfo = async (): Promise<RuntimeQueryIdSnapshotInfo | null> => {
     const snapshot = await loadSnapshot();
-    if (!snapshot) return null;
+    if (!snapshot) {
+      return null;
+    }
     const fetchedAtMs = new Date(snapshot.fetchedAt).getTime();
     const ageMs = Number.isFinite(fetchedAtMs) ? Math.max(0, Date.now() - fetchedAtMs) : Number.POSITIVE_INFINITY;
     const effectiveTtl = Number.isFinite(snapshot.ttlMs) ? snapshot.ttlMs : ttlMs;
@@ -235,7 +273,9 @@ export function createRuntimeQueryIdStore(options: RuntimeQueryIdsOptions = {})
 
   const getQueryId = async (operationName: string): Promise<string | null> => {
     const info = await getSnapshotInfo();
-    if (!info) return null;
+    if (!info) {
+      return null;
+    }
     return info.snapshot.ids[operationName] ?? null;
   };
 
@@ -243,7 +283,9 @@ export function createRuntimeQueryIdStore(options: RuntimeQueryIdsOptions = {})
     operationNames: string[],
     opts: { force?: boolean } = {},
   ): Promise<RuntimeQueryIdSnapshotInfo | null> => {
-    if (refreshInFlight) return refreshInFlight;
+    if (refreshInFlight) {
+      return refreshInFlight;
+    }
 
     refreshInFlight = (async () => {
       const current = await getSnapshotInfo();
diff --git a/src/lib/twitter-client.ts b/src/lib/twitter-client.ts
index e5f5379..2ef1946 100644
--- a/src/lib/twitter-client.ts
+++ b/src/lib/twitter-client.ts
@@ -4,6 +4,7 @@
 
 import { randomBytes, randomUUID } from 'node:crypto';
 import type { TwitterCookies } from './cookies.js';
+// biome-ignore lint/correctness/useImportExtensions: JSON module import doesn't use .js extension.
 import queryIds from './query-ids.json' with { type: 'json' };
 import { runtimeQueryIds } from './runtime-query-ids.js';
 
@@ -12,6 +13,9 @@ const TWITTER_GRAPHQL_POST_URL = 'https://x.com/i/api/graphql';
 const TWITTER_UPLOAD_URL = 'https://upload.twitter.com/i/media/upload.json';
 const TWITTER_MEDIA_METADATA_URL = 'https://x.com/i/api/1.1/media/metadata/create.json';
 const TWITTER_STATUS_UPDATE_URL = 'https://x.com/i/api/1.1/statuses/update.json';
+const SETTINGS_SCREEN_NAME_REGEX = /"screen_name":"([^"]+)"/;
+const SETTINGS_USER_ID_REGEX = /"user_id"\s*:\s*"(\d+)"/;
+const SETTINGS_NAME_REGEX = /"name":"([^"\\]*(?:\\.[^"\\]*)*)"/;
 
 // Query IDs rotate frequently; the values in query-ids.json are refreshed by
 // scripts/update-query-ids.ts. The fallback values keep the client usable if
@@ -339,7 +343,9 @@ export class TwitterClient {
       | undefined,
     tweetId: string,
   ) {
-    if (!instructions) return undefined;
+    if (!instructions) {
+      return undefined;
+    }
 
     for (const instruction of instructions) {
       for (const entry of instruction.entries || []) {
@@ -401,10 +407,14 @@ export class TwitterClient {
 
   private mediaCategoryForMime(mimeType: string): string | null {
     if (mimeType.startsWith('image/')) {
-      if (mimeType === 'image/gif') return 'tweet_gif';
+      if (mimeType === 'image/gif') {
+        return 'tweet_gif';
+      }
       return 'tweet_image';
     }
-    if (mimeType.startsWith('video/')) return 'tweet_video';
+    if (mimeType.startsWith('video/')) {
+      return 'tweet_video';
+    }
     return null;
   }
 
@@ -414,7 +424,9 @@ export class TwitterClient {
 
   async uploadMedia(input: { data: Uint8Array; mimeType: string; alt?: string }): Promise<UploadMediaResult> {
     const category = this.mediaCategoryForMime(input.mimeType);
-    if (!category) return { success: false, error: `Unsupported media type: ${input.mimeType}` };
+    if (!category) {
+      return { success: false, error: `Unsupported media type: ${input.mimeType}` };
+    }
 
     try {
       const initParams = new URLSearchParams({
@@ -442,7 +454,9 @@ export class TwitterClient {
           : initBody.media_id !== undefined
             ? String(initBody.media_id)
             : undefined;
-      if (!mediaId) return { success: false, error: 'Media upload INIT did not return media_id' };
+      if (!mediaId) {
+        return { success: false, error: 'Media upload INIT did not return media_id' };
+      }
 
       const chunkSize = 5 * 1024 * 1024;
       let segmentIndex = 0;
@@ -516,11 +530,15 @@ export class TwitterClient {
               error?: { message?: string; name?: string };
             };
           };
-          if (!statusBody.processing_info) break;
+          if (!statusBody.processing_info) {
+            break;
+          }
           info.state = statusBody.processing_info.state;
           info.check_after_secs = statusBody.processing_info.check_after_secs;
           info.error = statusBody.processing_info.error;
-          if (info.state === 'succeeded') break;
+          if (info.state === 'succeeded') {
+            break;
+          }
           attempts += 1;
         }
       }
@@ -547,15 +565,21 @@ export class TwitterClient {
     for (const value of values) {
       if (typeof value === 'string') {
         const trimmed = value.trim();
-        if (trimmed) return trimmed;
+        if (trimmed) {
+          return trimmed;
+        }
       }
     }
     return undefined;
   }
 
   private collectTextFields(value: unknown, keys: Set<string>, output: string[]): void {
-    if (!value) return;
-    if (typeof value === 'string') return;
+    if (!value) {
+      return;
+    }
+    if (typeof value === 'string') {
+      return;
+    }
 
     if (Array.isArray(value)) {
       for (const item of value) {
@@ -569,7 +593,9 @@ export class TwitterClient {
         if (keys.has(key)) {
           if (typeof nested === 'string') {
             const trimmed = nested.trim();
-            if (trimmed) output.push(trimmed);
+            if (trimmed) {
+              output.push(trimmed);
+            }
             continue;
           }
         }
@@ -582,7 +608,9 @@ export class TwitterClient {
     const seen = new Set<string>();
     const result: string[] = [];
     for (const value of values) {
-      if (seen.has(value)) continue;
+      if (seen.has(value)) {
+        continue;
+      }
       seen.add(value);
       result.push(value);
     }
@@ -591,7 +619,9 @@ export class TwitterClient {
 
   private extractArticleText(result: GraphqlTweetResult | undefined): string | undefined {
     const article = result?.article;
-    if (!article) return undefined;
+    if (!article) {
+      return undefined;
+    }
 
     const articleResult = article.article_results?.result ?? article;
     if (process.env.BIRD_DEBUG_ARTICLE === '1') {
@@ -656,7 +686,9 @@ export class TwitterClient {
 
   private extractNoteTweetText(result: GraphqlTweetResult | undefined): string | undefined {
     const note = result?.note_tweet?.note_tweet_results?.result;
-    if (!note) return undefined;
+    if (!note) {
+      return undefined;
+    }
 
     return this.firstText(
       note.text,
@@ -681,10 +713,14 @@ export class TwitterClient {
     const username = userLegacy?.screen_name ?? userCore?.screen_name;
     const name = userLegacy?.name ?? userCore?.name ?? username;
     const userId = userResult?.rest_id;
-    if (!result?.rest_id || !username) return undefined;
+    if (!result?.rest_id || !username) {
+      return undefined;
+    }
 
     const text = this.extractTweetText(result);
-    if (!text) return undefined;
+    if (!text) {
+      return undefined;
+    }
 
     return {
       id: result.rest_id,
@@ -742,7 +778,9 @@ export class TwitterClient {
   }): GraphqlTweetResult[] {
     const results: GraphqlTweetResult[] = [];
     const pushResult = (result?: GraphqlTweetResult) => {
-      if (result?.rest_id) results.push(result);
+      if (result?.rest_id) {
+        results.push(result);
+      }
     };
 
     const content = entry.content;
@@ -809,7 +847,9 @@ export class TwitterClient {
         const results = this.collectTweetResultsFromEntry(entry);
         for (const result of results) {
           const mapped = this.mapTweetResult(result);
-          if (!mapped || seen.has(mapped.id)) continue;
+          if (!mapped || seen.has(mapped.id)) {
+            continue;
+          }
           seen.add(mapped.id);
           tweets.push(mapped);
         }
@@ -990,7 +1030,9 @@ export class TwitterClient {
       for (const instruction of instructions) {
         for (const entry of instruction.entries ?? []) {
           const result = entry.content?.itemContent?.tweet_results?.result;
-          if (result?.rest_id !== tweetId) continue;
+          if (result?.rest_id !== tweetId) {
+            continue;
+          }
           const articleResult = result.article?.article_results?.result;
           const title = this.firstText(articleResult?.title, result.article?.title);
           const plainText = this.firstText(articleResult?.plain_text, result.article?.plain_text);
@@ -1352,12 +1394,16 @@ export class TwitterClient {
 
           if (data.errors && data.errors.length > 0) {
             const fallback = await this.tryStatusUpdateFallback(data.errors, variables);
-            if (fallback) return fallback;
+            if (fallback) {
+              return fallback;
+            }
             return { success: false, error: this.formatErrors(data.errors) };
           }
 
           const tweetId = data.data?.create_tweet?.tweet_results?.result?.rest_id;
-          if (tweetId) return { success: true, tweetId };
+          if (tweetId) {
+            return { success: true, tweetId };
+          }
 
           return { success: false, error: 'Tweet created but no ID returned' };
         }
@@ -1375,7 +1421,9 @@ export class TwitterClient {
 
       if (data.errors && data.errors.length > 0) {
         const fallback = await this.tryStatusUpdateFallback(data.errors, variables);
-        if (fallback) return fallback;
+        if (fallback) {
+          return fallback;
+        }
         return {
           success: false,
           error: this.formatErrors(data.errors),
@@ -1414,7 +1462,9 @@ export class TwitterClient {
     mediaIds?: string[];
   } | null {
     const text = typeof variables.tweet_text === 'string' ? variables.tweet_text : null;
-    if (!text) return null;
+    if (!text) {
+      return null;
+    }
 
     const reply = variables.reply;
     const inReplyToTweetId =
@@ -1486,7 +1536,9 @@ export class TwitterClient {
       const tweetId =
         typeof data.id_str === 'string' ? data.id_str : data.id !== undefined ? String(data.id) : undefined;
 
-      if (tweetId) return { success: true, tweetId };
+      if (tweetId) {
+        return { success: true, tweetId };
+      }
       return { success: false, error: 'Tweet created but no ID returned' };
     } catch (error) {
       return { success: false, error: error instanceof Error ? error.message : String(error) };
@@ -1497,12 +1549,18 @@ export class TwitterClient {
     errors: Array<{ message: string; code?: number }>,
     variables: Record<string, unknown>,
   ): Promise<TweetResult | null> {
-    if (!errors.some((error) => error.code === 226)) return null;
+    if (!errors.some((error) => error.code === 226)) {
+      return null;
+    }
     const input = this.statusUpdateInputFromCreateTweetVariables(variables);
-    if (!input) return null;
+    if (!input) {
+      return null;
+    }
 
     const fallback = await this.postStatusUpdate(input);
-    if (fallback.success) return fallback;
+    if (fallback.success) {
+      return fallback;
+    }
 
     return {
       success: false,
@@ -1511,8 +1569,12 @@ export class TwitterClient {
   }
 
   private async ensureClientUserId(): Promise<void> {
-    if (process.env.NODE_ENV === 'test') return;
-    if (this.clientUserId) return;
+    if (process.env.NODE_ENV === 'test') {
+      return;
+    }
+    if (this.clientUserId) {
+      return;
+    }
     const result = await this.getCurrentUser();
     if (result.success && result.user?.id) {
       this.clientUserId = result.user.id;
@@ -1622,12 +1684,16 @@ export class TwitterClient {
     };
 
     const firstAttempt = await tryOnce();
-    if (firstAttempt.success) return { success: true, tweets: firstAttempt.tweets };
+    if (firstAttempt.success) {
+      return { success: true, tweets: firstAttempt.tweets };
+    }
 
     if (firstAttempt.had404) {
       await this.refreshQueryIds();
       const secondAttempt = await tryOnce();
-      if (secondAttempt.success) return { success: true, tweets: secondAttempt.tweets };
+      if (secondAttempt.success) {
+        return { success: true, tweets: secondAttempt.tweets };
+      }
       return { success: false, error: secondAttempt.error };
     }
 
@@ -1729,9 +1795,9 @@ export class TwitterClient {
         }
 
         const html = await response.text();
-        const usernameMatch = html.match(/"screen_name":"([^"]+)"/);
-        const idMatch = html.match(/"user_id"\s*:\s*"(\d+)"/);
-        const nameMatch = html.match(/"name":"([^"\\]*(?:\\.[^"\\]*)*)"/);
+        const usernameMatch = SETTINGS_SCREEN_NAME_REGEX.exec(html);
+        const idMatch = SETTINGS_USER_ID_REGEX.exec(html);
+        const nameMatch = SETTINGS_NAME_REGEX.exec(html);
 
         const username = usernameMatch?.[1];
         const userId = idMatch?.[1];
@@ -1765,7 +1831,9 @@ export class TwitterClient {
    */
   async getReplies(tweetId: string): Promise<SearchResult> {
     const response = await this.fetchTweetDetail(tweetId);
-    if (!response.success) return response;
+    if (!response.success) {
+      return response;
+    }
 
     const instructions = response.data.threaded_conversation_with_injections_v2?.instructions;
     const tweets = this.parseTweetsFromInstructions(instructions);
@@ -1779,7 +1847,9 @@ export class TwitterClient {
    */
   async getThread(tweetId: string): Promise<SearchResult> {
     const response = await this.fetchTweetDetail(tweetId);
-    if (!response.success) return response;
+    if (!response.success) {
+      return response;
+    }
 
     const instructions = response.data.threaded_conversation_with_injections_v2?.instructions;
     const tweets = this.parseTweetsFromInstructions(instructions);
@@ -1899,12 +1969,16 @@ export class TwitterClient {
     };
 
     const firstAttempt = await tryOnce();
-    if (firstAttempt.success) return { success: true, tweets: firstAttempt.tweets };
+    if (firstAttempt.success) {
+      return { success: true, tweets: firstAttempt.tweets };
+    }
 
     if (firstAttempt.had404) {
       await this.refreshQueryIds();
       const secondAttempt = await tryOnce();
-      if (secondAttempt.success) return { success: true, tweets: secondAttempt.tweets };
+      if (secondAttempt.success) {
+        return { success: true, tweets: secondAttempt.tweets };
+      }
       return { success: false, error: secondAttempt.error };
     }
 
diff --git a/src/lib/version.ts b/src/lib/version.ts
index 5a1fb0b..685fb46 100644
--- a/src/lib/version.ts
+++ b/src/lib/version.ts
@@ -5,6 +5,9 @@ import { fileURLToPath } from 'node:url';
 declare const __dirname: string | undefined;
 
 export const FALLBACK_VERSION = 'unknown';
+const REF_PREFIX_REGEX = /^ref:\s*/i;
+const LINE_SPLIT_REGEX = /\r?\n/;
+const GITDIR_REGEX = /gitdir:\s*(.+)\s*$/i;
 
 function readPackageVersionFromJsonFile(candidate: string): string | null {
   try {
@@ -37,7 +40,9 @@ function resolveStartDir(importMetaUrl?: string): string {
     }
   }
 
-  if (typeof __dirname === 'string' && __dirname.length > 0) return __dirname;
+  if (typeof __dirname === 'string' && __dirname.length > 0) {
+    return __dirname;
+  }
 
   return process.cwd();
 }
@@ -47,27 +52,37 @@ export function resolvePackageVersion(importMetaUrl?: string): string {
     typeof process !== 'undefined' && typeof process.env.BIRD_VERSION === 'string'
       ? process.env.BIRD_VERSION.trim()
       : '';
-  if (injected.length > 0) return injected;
+  if (injected.length > 0) {
+    return injected;
+  }
 
   let dir = resolveStartDir(importMetaUrl);
   for (let i = 0; i < 10; i += 1) {
     const version =
       readPackageVersionFromJsonFile(path.join(dir, 'package.json')) ??
       readVersionFromTextFile(path.join(dir, 'VERSION'));
-    if (version) return version;
+    if (version) {
+      return version;
+    }
 
     const parent = path.dirname(dir);
-    if (parent === dir) break;
+    if (parent === dir) {
+      break;
+    }
     dir = parent;
   }
 
   return FALLBACK_VERSION;
 }
 
-function truncateSha(sha: string, length = 8): string {
+function truncateSha(sha: string, length: number = 8): string {
   const trimmed = sha.trim();
-  if (!trimmed) return '';
-  if (trimmed.length <= length) return trimmed;
+  if (!trimmed) {
+    return '';
+  }
+  if (trimmed.length <= length) {
+    return trimmed;
+  }
   return trimmed.slice(0, length);
 }
 
@@ -80,14 +95,18 @@ function resolveGitShaFromGitDir(gitDir: string): string | null {
     return null;
   }
 
-  if (!head) return null;
+  if (!head) {
+    return null;
+  }
   if (!head.startsWith('ref:')) {
     const sha = truncateSha(head);
     return sha.length > 0 ? sha : null;
   }
 
-  const ref = head.replace(/^ref:\s*/i, '').trim();
-  if (!ref) return null;
+  const ref = head.replace(REF_PREFIX_REGEX, '').trim();
+  if (!ref) {
+    return null;
+  }
 
   const refPath = path.join(gitDir, ref);
   try {
@@ -100,9 +119,11 @@ function resolveGitShaFromGitDir(gitDir: string): string | null {
   const packedRefsPath = path.join(gitDir, 'packed-refs');
   try {
     const packed = fs.readFileSync(packedRefsPath, 'utf8');
-    const lines = packed.split(/\r?\n/);
+    const lines = packed.split(LINE_SPLIT_REGEX);
     for (const line of lines) {
-      if (!line || line.startsWith('#') || line.startsWith('^')) continue;
+      if (!line || line.startsWith('#') || line.startsWith('^')) {
+        continue;
+      }
       const [shaRaw, refName] = line.split(' ');
       if (refName?.trim() === ref) {
         const sha = truncateSha(shaRaw ?? '');
@@ -121,7 +142,9 @@ export function resolveGitSha(importMetaUrl?: string): string | null {
     typeof process !== 'undefined' && typeof process.env.BIRD_GIT_SHA === 'string'
       ? process.env.BIRD_GIT_SHA.trim()
       : '';
-  if (injected.length > 0) return truncateSha(injected);
+  if (injected.length > 0) {
+    return truncateSha(injected);
+  }
 
   let dir = resolveStartDir(importMetaUrl);
   for (let i = 0; i < 10; i += 1) {
@@ -130,15 +153,19 @@ export function resolveGitSha(importMetaUrl?: string): string | null {
       const stat = fs.statSync(dotGit);
       if (stat.isDirectory()) {
         const sha = resolveGitShaFromGitDir(dotGit);
-        if (sha) return sha;
+        if (sha) {
+          return sha;
+        }
       } else if (stat.isFile()) {
         const txt = fs.readFileSync(dotGit, 'utf8');
-        const match = txt.match(/gitdir:\s*(.+)\s*$/i);
+        const match = GITDIR_REGEX.exec(txt);
         const gitDir = match?.[1]?.trim();
         if (gitDir) {
           const resolved = path.isAbsolute(gitDir) ? gitDir : path.resolve(dir, gitDir);
           const sha = resolveGitShaFromGitDir(resolved);
-          if (sha) return sha;
+          if (sha) {
+            return sha;
+          }
         }
       }
     } catch {
@@ -146,7 +173,9 @@ export function resolveGitSha(importMetaUrl?: string): string | null {
     }
 
     const parent = path.dirname(dir);
-    if (parent === dir) break;
+    if (parent === dir) {
+      break;
+    }
     dir = parent;
   }
 
diff --git a/tests/cookies.test.ts b/tests/cookies.test.ts
index 23d6ce8..849732b 100644
--- a/tests/cookies.test.ts
+++ b/tests/cookies.test.ts
@@ -191,6 +191,57 @@ describe('cookies', () => {
       expect(result.cookies.ct0).toBe('test_ct0');
       expect(result.cookies.source).toContain('Chrome');
     });
+
+    it('uses default browser order when cookieSource is omitted', async () => {
+      sweet.results.set('safari', { cookies: [], warnings: [] });
+      sweet.results.set('chrome', { cookies: [], warnings: [] });
+      sweet.results.set('firefox', {
+        cookies: [
+          { name: 'auth_token', value: 'firefox_auth', domain: 'x.com' },
+          { name: 'ct0', value: 'firefox_ct0', domain: 'x.com' },
+        ],
+        warnings: [],
+      });
+
+      const { resolveCredentials } = await import('../src/lib/cookies.js');
+      const result = await resolveCredentials({});
+
+      expect(result.cookies.authToken).toBe('firefox_auth');
+      expect(result.cookies.ct0).toBe('firefox_ct0');
+      expect(result.cookies.source).toContain('Firefox');
+    });
+
+    it('prefers twitter.com cookies when x.com is missing', async () => {
+      sweet.results.set('chrome', {
+        cookies: [
+          { name: 'auth_token', value: 'twitter_auth', domain: 'twitter.com' },
+          { name: 'ct0', value: 'twitter_ct0', domain: 'twitter.com' },
+        ],
+        warnings: [],
+      });
+
+      const { resolveCredentials } = await import('../src/lib/cookies.js');
+      const result = await resolveCredentials({ cookieSource: 'chrome' });
+
+      expect(result.cookies.authToken).toBe('twitter_auth');
+      expect(result.cookies.ct0).toBe('twitter_ct0');
+    });
+
+    it('falls back to the first cookie when no domain matches', async () => {
+      sweet.results.set('firefox', {
+        cookies: [
+          { name: 'auth_token', value: 'first_auth', domain: 'example.com' },
+          { name: 'ct0', value: 'first_ct0', domain: 'example.com' },
+        ],
+        warnings: [],
+      });
+
+      const { resolveCredentials } = await import('../src/lib/cookies.js');
+      const result = await resolveCredentials({ cookieSource: 'firefox' });
+
+      expect(result.cookies.authToken).toBe('first_auth');
+      expect(result.cookies.ct0).toBe('first_ct0');
+    });
   });
 
   describe('extractCookiesFromSafari', () => {
diff --git a/tests/normalize-handle.test.ts b/tests/normalize-handle.test.ts
index 89de4a6..522fd14 100644
--- a/tests/normalize-handle.test.ts
+++ b/tests/normalize-handle.test.ts
@@ -1,6 +1,8 @@
 import { describe, expect, it } from 'vitest';
 import { mentionsQueryFromUserOption, normalizeHandle } from '../src/lib/normalize-handle.js';
 
+const INVALID_HANDLE_REGEX = /Invalid --user handle/;
+
 describe('normalizeHandle', () => {
   it('accepts bare handle', () => {
     expect(normalizeHandle('steipete')).toBe('steipete');
@@ -36,6 +38,6 @@ describe('mentionsQueryFromUserOption', () => {
   it('returns error for invalid handle', () => {
     const result = mentionsQueryFromUserOption('@stei-pete');
     expect(result.query).toBeNull();
-    expect(result.error).toMatch(/Invalid --user handle/);
+    expect(result.error).toMatch(INVALID_HANDLE_REGEX);
   });
 });
diff --git a/tests/runtime-query-ids.test.ts b/tests/runtime-query-ids.test.ts
index 0cc72aa..f6624cd 100644
--- a/tests/runtime-query-ids.test.ts
+++ b/tests/runtime-query-ids.test.ts
@@ -1,5 +1,5 @@
 import { randomUUID } from 'node:crypto';
-import { mkdir, readFile } from 'node:fs/promises';
+import { mkdir, readFile, writeFile } from 'node:fs/promises';
 import os from 'node:os';
 import path from 'node:path';
 import { afterEach, describe, expect, it, vi } from 'vitest';
@@ -8,6 +8,7 @@ import { createRuntimeQueryIdStore } from '../src/lib/runtime-query-ids.js';
 describe('runtime-query-ids', () => {
   afterEach(() => {
     vi.unstubAllGlobals();
+    delete process.env.BIRD_QUERY_IDS_CACHE;
   });
 
   it('refreshes IDs by scanning discovered bundles and persists cache', async () => {
@@ -60,4 +61,83 @@ describe('runtime-query-ids', () => {
     const parsed = JSON.parse(raw) as { ids?: Record<string, string> };
     expect(parsed.ids?.SearchTimeline).toBe('EEE');
   });
+
+  it('uses env cache path override and returns fresh snapshot without refreshing', async () => {
+    const cacheDir = path.join(os.tmpdir(), `bird-test-${randomUUID()}`);
+    await mkdir(cacheDir, { recursive: true });
+    const cachePath = path.join(cacheDir, 'query-ids-cache.json');
+    process.env.BIRD_QUERY_IDS_CACHE = cachePath;
+
+    const snapshot = {
+      fetchedAt: new Date().toISOString(),
+      ttlMs: 60_000,
+      ids: { CreateTweet: 'AAA' },
+      discovery: { pages: ['https://x.com/'], bundles: ['main.js'] },
+    };
+    await writeFile(cachePath, JSON.stringify(snapshot), 'utf8');
+
+    const fetchMock = vi.fn();
+    const store = createRuntimeQueryIdStore({ fetchImpl: fetchMock as unknown as typeof fetch });
+    const info = await store.refresh(['CreateTweet']);
+
+    expect(store.cachePath).toBe(cachePath);
+    expect(info?.snapshot.ids.CreateTweet).toBe('AAA');
+    expect(fetchMock).not.toHaveBeenCalled();
+
+    store.clearMemory();
+  });
+
+  it('returns current snapshot when refresh finds no matching operations', async () => {
+    const cacheDir = path.join(os.tmpdir(), `bird-test-${randomUUID()}`);
+    await mkdir(cacheDir, { recursive: true });
+    const cachePath = path.join(cacheDir, 'query-ids.json');
+
+    const snapshot = {
+      fetchedAt: new Date(0).toISOString(),
+      ttlMs: 1,
+      ids: { CreateTweet: 'AAA' },
+      discovery: { pages: ['https://x.com/'], bundles: ['main.test.js'] },
+    };
+    await writeFile(cachePath, JSON.stringify(snapshot), 'utf8');
+
+    const html = `<script src="https://abs.twimg.com/responsive-web/client-web/main.test.js"></script>`;
+    const js = 'console.log("no ops here")';
+
+    const fetchMock = vi.fn(async (url: string | URL) => {
+      const asString = String(url);
+      if (asString.startsWith('https://x.com/')) {
+        return new Response(html, { status: 200 });
+      }
+      if (asString.startsWith('https://abs.twimg.com/')) {
+        return new Response(js, { status: 200 });
+      }
+      return new Response('not found', { status: 404 });
+    });
+
+    const store = createRuntimeQueryIdStore({
+      cachePath,
+      ttlMs: 1,
+      fetchImpl: fetchMock as unknown as typeof fetch,
+    });
+
+    const info = await store.refresh(['CreateTweet']);
+    expect(info?.snapshot.ids.CreateTweet).toBe('AAA');
+  });
+
+  it('throws when no bundles can be discovered', async () => {
+    const cacheDir = path.join(os.tmpdir(), `bird-test-${randomUUID()}`);
+    await mkdir(cacheDir, { recursive: true });
+    const cachePath = path.join(cacheDir, 'query-ids.json');
+
+    const fetchMock = vi.fn(async () => new Response('nope', { status: 500 }));
+
+    const store = createRuntimeQueryIdStore({
+      cachePath,
+      fetchImpl: fetchMock as unknown as typeof fetch,
+    });
+
+    await expect(store.refresh(['CreateTweet'], { force: true })).rejects.toThrow(
+      'No client bundles discovered; x.com layout may have changed.',
+    );
+  });
 });
diff --git a/tests/twitter-client-coverage.api.test.ts b/tests/twitter-client-coverage.api.test.ts
new file mode 100644
index 0000000..7083dc6
--- /dev/null
+++ b/tests/twitter-client-coverage.api.test.ts
@@ -0,0 +1,207 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { TwitterClient } from '../src/lib/twitter-client.js';
+
+const validCookies = {
+  authToken: 'test_auth_token',
+  ct0: 'test_ct0_token',
+  cookieHeader: 'auth_token=test_auth_token; ct0=test_ct0_token',
+  source: 'test',
+};
+
+type ResponseLike = {
+  ok: boolean;
+  status: number;
+  json: () => Promise<unknown>;
+  text: () => Promise<string>;
+};
+
+type TwitterClientApiPrivate = TwitterClient & {
+  getBookmarksQueryIds: () => Promise<string[]>;
+};
+
+const makeResponse = (overrides: Partial<ResponseLike> = {}): ResponseLike => ({
+  ok: true,
+  status: 200,
+  json: async (): Promise<unknown> => ({}),
+  text: async (): Promise<string> => '',
+  ...overrides,
+});
+
+describe('TwitterClient API coverage', () => {
+  const originalFetch = global.fetch;
+
+  afterEach(() => {
+    global.fetch = originalFetch;
+    vi.restoreAllMocks();
+  });
+
+  describe('createTweet fallback paths', () => {
+    it('returns an error when retry response is not ok', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 404, text: async () => 'nope' }))
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 404, text: async () => 'nope' }))
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'boom' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.tweet('hi');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('HTTP 500');
+    });
+
+    it('returns API errors when retry response contains errors', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 404, text: async () => 'nope' }))
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 404, text: async () => 'nope' }))
+        .mockResolvedValueOnce(
+          makeResponse({
+            json: async () => ({ errors: [{ message: 'rate limited', code: 1 }] }),
+          }),
+        );
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.tweet('hi');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('rate limited');
+    });
+
+    it('returns an error when retry response has no tweet id', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 404, text: async () => 'nope' }))
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 404, text: async () => 'nope' }))
+        .mockResolvedValueOnce(
+          makeResponse({
+            json: async () => ({ data: { create_tweet: { tweet_results: { result: {} } } } }),
+          }),
+        );
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.tweet('hi');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('no ID');
+    });
+  });
+
+  describe('search error paths', () => {
+    it('returns an error for non-ok responses', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'down' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.search('test');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('HTTP 500');
+    });
+
+    it('returns errors from payloads', async () => {
+      const mockFetch = vi.fn().mockResolvedValueOnce(
+        makeResponse({
+          json: async () => ({ errors: [{ message: 'bad' }] }),
+        }),
+      );
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.search('test');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('bad');
+    });
+
+    it('returns an error when fetching throws', async () => {
+      const mockFetch = vi.fn().mockRejectedValue(new Error('boom'));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.search('test');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('boom');
+    });
+
+    it('returns the second attempt error after 404s', async () => {
+      const mockFetch = vi.fn().mockResolvedValue(makeResponse({ ok: false, status: 404, text: async () => 'nope' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.search('test');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('HTTP 404');
+    });
+  });
+
+  describe('bookmarks error paths', () => {
+    it('returns an error for non-ok responses', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'down' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.getBookmarks(1);
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('HTTP 500');
+    });
+
+    it('returns API errors from payloads', async () => {
+      const mockFetch = vi.fn().mockResolvedValueOnce(
+        makeResponse({
+          json: async () => ({ errors: [{ message: 'bad' }] }),
+        }),
+      );
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.getBookmarks(1);
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('bad');
+    });
+
+    it('returns an error when fetching throws', async () => {
+      const mockFetch = vi.fn().mockRejectedValue(new Error('boom'));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.getBookmarks(1);
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('boom');
+    });
+
+    it('returns unknown error when no query ids are available', async () => {
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientApiPrivate;
+      clientPrivate.getBookmarksQueryIds = async () => [];
+
+      const result = await client.getBookmarks(1);
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('Unknown error fetching bookmarks');
+    });
+
+    it('returns the second attempt error after 404s', async () => {
+      const mockFetch = vi.fn().mockResolvedValue(makeResponse({ ok: false, status: 404, text: async () => 'nope' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.getBookmarks(1);
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('HTTP 404');
+    });
+  });
+});
diff --git a/tests/twitter-client-coverage.core.test.ts b/tests/twitter-client-coverage.core.test.ts
new file mode 100644
index 0000000..ed94c81
--- /dev/null
+++ b/tests/twitter-client-coverage.core.test.ts
@@ -0,0 +1,248 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { runtimeQueryIds } from '../src/lib/runtime-query-ids.js';
+import { TwitterClient } from '../src/lib/twitter-client.js';
+
+const validCookies = {
+  authToken: 'test_auth_token',
+  ct0: 'test_ct0_token',
+  cookieHeader: 'auth_token=test_auth_token; ct0=test_ct0_token',
+  source: 'test',
+};
+
+type ResponseLike = {
+  ok: boolean;
+  status: number;
+  json: () => Promise<unknown>;
+  text: () => Promise<string>;
+};
+
+type TwitterClientPrivate = TwitterClient & {
+  refreshQueryIds: () => Promise<void>;
+  fetchWithTimeout: (url: string, init: RequestInit) => Promise<ResponseLike>;
+  ensureClientUserId: () => Promise<void>;
+  getBaseHeaders: () => Record<string, string>;
+  fetchUserArticlePlainText: (userId: string, tweetId: string) => Promise<{ title?: string; plainText?: string }>;
+  fetchTweetDetail: (tweetId: string) => Promise<{ success: true } | { success: false; error: string }>;
+  postStatusUpdate: (input: { text: string }) => Promise<{ success: boolean; error?: string }>;
+};
+
+const makeResponse = (overrides: Partial<ResponseLike> = {}): ResponseLike => ({
+  ok: true,
+  status: 200,
+  json: async (): Promise<unknown> => ({}),
+  text: async (): Promise<string> => '',
+  ...overrides,
+});
+
+describe('TwitterClient core coverage', () => {
+  const originalFetch = global.fetch;
+  const originalNodeEnv = process.env.NODE_ENV;
+
+  afterEach(() => {
+    global.fetch = originalFetch;
+    process.env.NODE_ENV = originalNodeEnv;
+    delete process.env.BIRD_DEBUG_ARTICLE;
+    vi.restoreAllMocks();
+  });
+
+  it('refreshQueryIds calls runtime refresh outside test env', async () => {
+    const client = new TwitterClient({ cookies: validCookies });
+    const refreshSpy = vi.spyOn(runtimeQueryIds, 'refresh').mockResolvedValue(null);
+    process.env.NODE_ENV = 'production';
+
+    const clientPrivate = client as unknown as TwitterClientPrivate;
+    await clientPrivate.refreshQueryIds();
+
+    expect(refreshSpy).toHaveBeenCalled();
+  });
+
+  it('fetchWithTimeout uses an abort signal when timeout is set', async () => {
+    const mockFetch = vi.fn(async (_url: string, init?: RequestInit) => {
+      expect(init?.signal).toBeInstanceOf(AbortSignal);
+      return makeResponse();
+    });
+    global.fetch = mockFetch as unknown as typeof fetch;
+
+    const client = new TwitterClient({ cookies: validCookies, timeoutMs: 5 });
+    const clientPrivate = client as unknown as TwitterClientPrivate;
+    await clientPrivate.fetchWithTimeout('https://example.com', { method: 'GET' });
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+  });
+
+  it('returns a not found error when tweet data is missing', async () => {
+    const mockFetch = vi.fn().mockResolvedValueOnce(
+      makeResponse({
+        json: async () => ({
+          data: {
+            threaded_conversation_with_injections_v2: {
+              instructions: [
+                {
+                  entries: [
+                    {
+                      content: {
+                        itemContent: {
+                          tweet_results: {
+                            result: {
+                              rest_id: 'other',
+                              legacy: { full_text: 'nope', created_at: '2024-01-01T00:00:00Z' },
+                              core: { user_results: { result: { legacy: { screen_name: 'user', name: 'User' } } } },
+                            },
+                          },
+                        },
+                      },
+                    },
+                  ],
+                },
+              ],
+            },
+          },
+        }),
+      }),
+    );
+    global.fetch = mockFetch as unknown as typeof fetch;
+
+    const client = new TwitterClient({ cookies: validCookies });
+    const result = await client.getTweet('123');
+
+    expect(result.success).toBe(false);
+    expect(result.error).toBe('Tweet not found in response');
+  });
+
+  it('adds client user id header after ensureClientUserId', async () => {
+    const client = new TwitterClient({ cookies: validCookies });
+    process.env.NODE_ENV = 'production';
+
+    vi.spyOn(client, 'getCurrentUser').mockResolvedValue({
+      success: true,
+      user: { id: '42', username: 'tester', name: 'Tester' },
+    });
+
+    const clientPrivate = client as unknown as TwitterClientPrivate;
+    await clientPrivate.ensureClientUserId();
+    const headers = clientPrivate.getBaseHeaders();
+
+    expect(headers['x-twitter-client-user-id']).toBe('42');
+  });
+
+  describe('fetchUserArticlePlainText failures', () => {
+    it('returns empty object when response is not ok', async () => {
+      const mockFetch = vi.fn().mockResolvedValueOnce(makeResponse({ ok: false, status: 500 }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientPrivate;
+      const result = await clientPrivate.fetchUserArticlePlainText('user', 'tweet');
+
+      expect(result).toEqual({});
+    });
+
+    it('returns empty object when fetching throws', async () => {
+      const mockFetch = vi.fn().mockRejectedValueOnce(new Error('boom'));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientPrivate;
+      const result = await clientPrivate.fetchUserArticlePlainText('user', 'tweet');
+
+      expect(result).toEqual({});
+    });
+
+    it('returns empty object when no matching tweet is found', async () => {
+      const mockFetch = vi.fn().mockResolvedValueOnce(
+        makeResponse({
+          json: async () => ({
+            data: {
+              user: { result: { timeline: { timeline: { instructions: [] } } } },
+            },
+          }),
+        }),
+      );
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientPrivate;
+      const result = await clientPrivate.fetchUserArticlePlainText('user', 'tweet');
+
+      expect(result).toEqual({});
+    });
+  });
+
+  describe('fetchTweetDetail error handling', () => {
+    it('returns API errors from response payloads', async () => {
+      const mockFetch = vi.fn().mockResolvedValueOnce(
+        makeResponse({
+          json: async () => ({ errors: [{ message: 'bad news' }] }),
+        }),
+      );
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientPrivate;
+      const result = await clientPrivate.fetchTweetDetail('1');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('bad news');
+    });
+
+    it('parses POST responses when GET returns 404', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 404, text: async () => 'nope' }))
+        .mockResolvedValueOnce(
+          makeResponse({
+            json: async () => ({
+              data: {
+                tweetResult: {
+                  result: {
+                    rest_id: '1',
+                    legacy: {
+                      full_text: 'hi',
+                      created_at: '2024-01-01T00:00:00Z',
+                      reply_count: 0,
+                      retweet_count: 0,
+                      favorite_count: 0,
+                    },
+                    core: { user_results: { result: { legacy: { screen_name: 'user', name: 'User' } } } },
+                  },
+                },
+              },
+            }),
+          }),
+        );
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientPrivate;
+      const result = await clientPrivate.fetchTweetDetail('1');
+
+      expect(result.success).toBe(true);
+    });
+
+    it('returns an error when fetch throws', async () => {
+      const mockFetch = vi.fn().mockRejectedValueOnce(new Error('boom'));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientPrivate;
+      const result = await clientPrivate.fetchTweetDetail('1');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('boom');
+    });
+  });
+
+  describe('postStatusUpdate error handling', () => {
+    it('returns an error when postStatusUpdate throws', async () => {
+      const mockFetch = vi.fn().mockRejectedValueOnce(new Error('boom'));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientPrivate;
+      const result = await clientPrivate.postStatusUpdate({ text: 'hello' });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('boom');
+    });
+  });
+});
diff --git a/tests/twitter-client-coverage.upload.test.ts b/tests/twitter-client-coverage.upload.test.ts
new file mode 100644
index 0000000..00c2555
--- /dev/null
+++ b/tests/twitter-client-coverage.upload.test.ts
@@ -0,0 +1,224 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { TwitterClient } from '../src/lib/twitter-client.js';
+
+const validCookies = {
+  authToken: 'test_auth_token',
+  ct0: 'test_ct0_token',
+  cookieHeader: 'auth_token=test_auth_token; ct0=test_ct0_token',
+  source: 'test',
+};
+
+type ResponseLike = {
+  ok: boolean;
+  status: number;
+  json: () => Promise<unknown>;
+  text: () => Promise<string>;
+};
+
+type TwitterClientUploadPrivate = TwitterClient & {
+  sleep: (ms: number) => Promise<void>;
+  extractArticleText: (result: unknown) => string | undefined;
+};
+
+const makeResponse = (overrides: Partial<ResponseLike> = {}): ResponseLike => ({
+  ok: true,
+  status: 200,
+  json: async (): Promise<unknown> => ({}),
+  text: async (): Promise<string> => '',
+  ...overrides,
+});
+
+describe('TwitterClient upload coverage', () => {
+  const originalFetch = global.fetch;
+
+  afterEach(() => {
+    global.fetch = originalFetch;
+    delete process.env.BIRD_DEBUG_ARTICLE;
+    vi.restoreAllMocks();
+  });
+
+  describe('uploadMedia error paths', () => {
+    it('rejects unsupported media types', async () => {
+      global.fetch = vi.fn() as unknown as typeof fetch;
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.uploadMedia({ data: new Uint8Array([1, 2, 3]), mimeType: 'application/pdf' });
+
+      expect(result.success).toBe(false);
+      expect(global.fetch).not.toHaveBeenCalled();
+    });
+
+    it('returns an error when INIT fails', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'nope' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.uploadMedia({ data: new Uint8Array([1]), mimeType: 'image/png' });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('HTTP 500');
+    });
+
+    it('returns an error when APPEND fails', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ json: async () => ({ media_id_string: '1' }) }))
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'nope' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.uploadMedia({ data: new Uint8Array([1]), mimeType: 'image/png' });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('HTTP 500');
+    });
+
+    it('returns an error when FINALIZE fails', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ json: async () => ({ media_id_string: '1' }) }))
+        .mockResolvedValueOnce(makeResponse())
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 500, text: async () => 'nope' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.uploadMedia({ data: new Uint8Array([1]), mimeType: 'image/png' });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('HTTP 500');
+    });
+
+    it('returns an error when media processing fails', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ json: async () => ({ media_id_string: '1' }) }))
+        .mockResolvedValueOnce(makeResponse())
+        .mockResolvedValueOnce(
+          makeResponse({
+            json: async () => ({ processing_info: { state: 'failed', error: { message: 'processing failed' } } }),
+          }),
+        );
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.uploadMedia({ data: new Uint8Array([1]), mimeType: 'video/mp4' });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('processing failed');
+    });
+
+    it('returns an error when STATUS fails', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ json: async () => ({ media_id_string: '1' }) }))
+        .mockResolvedValueOnce(makeResponse())
+        .mockResolvedValueOnce(
+          makeResponse({
+            json: async () => ({ processing_info: { state: 'pending', check_after_secs: 0 } }),
+          }),
+        )
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 503, text: async () => 'down' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientUploadPrivate;
+      clientPrivate.sleep = vi.fn().mockResolvedValue(undefined);
+
+      const result = await client.uploadMedia({ data: new Uint8Array([1]), mimeType: 'video/mp4' });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('HTTP 503');
+    });
+
+    it('retries STATUS and continues when processing is pending', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ json: async () => ({ media_id_string: '1' }) }))
+        .mockResolvedValueOnce(makeResponse())
+        .mockResolvedValueOnce(
+          makeResponse({
+            json: async () => ({ processing_info: { state: 'pending', check_after_secs: 0 } }),
+          }),
+        )
+        .mockResolvedValueOnce(
+          makeResponse({
+            json: async () => ({ processing_info: { state: 'pending', check_after_secs: 0 } }),
+          }),
+        )
+        .mockResolvedValueOnce(makeResponse({ json: async () => ({ processing_info: { state: 'succeeded' } }) }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientUploadPrivate;
+      clientPrivate.sleep = vi.fn().mockResolvedValue(undefined);
+
+      const result = await client.uploadMedia({ data: new Uint8Array([1]), mimeType: 'video/mp4' });
+
+      expect(result.success).toBe(true);
+    });
+
+    it('returns an error when metadata upload fails', async () => {
+      const mockFetch = vi
+        .fn()
+        .mockResolvedValueOnce(makeResponse({ json: async () => ({ media_id_string: '1' }) }))
+        .mockResolvedValueOnce(makeResponse())
+        .mockResolvedValueOnce(makeResponse({ json: async () => ({}) }))
+        .mockResolvedValueOnce(makeResponse({ ok: false, status: 400, text: async () => 'bad' }));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.uploadMedia({ data: new Uint8Array([1]), mimeType: 'image/png', alt: 'alt' });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('HTTP 400');
+    });
+
+    it('returns an error when upload throws', async () => {
+      const mockFetch = vi.fn().mockRejectedValueOnce(new Error('boom'));
+      global.fetch = mockFetch as unknown as typeof fetch;
+
+      const client = new TwitterClient({ cookies: validCookies });
+      const result = await client.uploadMedia({ data: new Uint8Array([1]), mimeType: 'image/png' });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain('boom');
+    });
+  });
+
+  describe('article extraction edge cases', () => {
+    it('logs article payloads when debug flag is set', () => {
+      const client = new TwitterClient({ cookies: validCookies });
+      process.env.BIRD_DEBUG_ARTICLE = '1';
+      const errorSpy = vi.spyOn(console, 'error').mockImplementation(() => {});
+
+      const clientPrivate = client as unknown as TwitterClientUploadPrivate;
+      const result = clientPrivate.extractArticleText({
+        rest_id: '1',
+        article: {
+          title: 'Title',
+          plain_text: 'Body',
+          article_results: { result: { title: 'Title', plain_text: 'Body' } },
+        },
+      });
+
+      expect(result).toBe('Title\n\nBody');
+      expect(errorSpy).toHaveBeenCalled();
+    });
+
+    it('drops duplicate body when it matches the title', () => {
+      const client = new TwitterClient({ cookies: validCookies });
+      const clientPrivate = client as unknown as TwitterClientUploadPrivate;
+      const result = clientPrivate.extractArticleText({
+        rest_id: '1',
+        article: {
+          title: 'Same',
+          plain_text: 'Same',
+          article_results: { result: { title: 'Same', plain_text: 'Same' } },
+        },
+      });
+
+      expect(result).toBe('Same');
+    });
+  });
+});
diff --git a/tests/version.test.ts b/tests/version.test.ts
index 75d6439..9bb2422 100644
--- a/tests/version.test.ts
+++ b/tests/version.test.ts
@@ -3,7 +3,13 @@ import os from 'node:os';
 import path from 'node:path';
 import { fileURLToPath, pathToFileURL } from 'node:url';
 import { afterEach, describe, expect, it } from 'vitest';
-import { FALLBACK_VERSION, formatVersionLine, resolveGitSha, resolvePackageVersion } from '../src/lib/version.js';
+import {
+  FALLBACK_VERSION,
+  formatVersionLine,
+  getCliVersion,
+  resolveGitSha,
+  resolvePackageVersion,
+} from '../src/lib/version.js';
 
 function withTempDir<T>(fn: (dir: string) => T): T {
   const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'bird-version-test-'));
@@ -53,6 +59,17 @@ describe('getCliVersion', () => {
     });
   });
 
+  it('falls back to VERSION file when package.json has no version', () => {
+    withTempDir((dir) => {
+      fs.writeFileSync(path.join(dir, 'package.json'), JSON.stringify({}));
+      fs.writeFileSync(path.join(dir, 'VERSION'), '5.5.5\n');
+      const entry = path.join(dir, 'entry.ts');
+      fs.writeFileSync(entry, '// noop');
+
+      expect(resolvePackageVersion(pathToFileURL(entry).href)).toBe('5.5.5');
+    });
+  });
+
   it('falls back to unknown when no version files exist', () => {
     withTempDir((dir) => {
       const entry = path.join(dir, 'a', 'b', 'c', 'entry.ts');
@@ -63,6 +80,31 @@ describe('getCliVersion', () => {
     });
   });
 
+  it('returns null when git HEAD is missing', () => {
+    withTempDir((dir) => {
+      const gitDir = path.join(dir, '.git');
+      fs.mkdirSync(gitDir, { recursive: true });
+
+      const entry = path.join(dir, 'entry.ts');
+      fs.writeFileSync(entry, '// noop');
+
+      expect(resolveGitSha(pathToFileURL(entry).href)).toBeNull();
+    });
+  });
+
+  it('returns null when git ref cannot be resolved', () => {
+    withTempDir((dir) => {
+      const gitDir = path.join(dir, '.git');
+      fs.mkdirSync(gitDir, { recursive: true });
+      fs.writeFileSync(path.join(gitDir, 'HEAD'), 'ref: refs/heads/main\n');
+
+      const entry = path.join(dir, 'entry.ts');
+      fs.writeFileSync(entry, '// noop');
+
+      expect(resolveGitSha(pathToFileURL(entry).href)).toBeNull();
+    });
+  });
+
   it('resolves git sha from .git directory HEAD', () => {
     withTempDir((dir) => {
       const gitDir = path.join(dir, '.git');
@@ -113,6 +155,16 @@ describe('getCliVersion', () => {
     });
   });
 
+  it('returns null when no git directory exists', () => {
+    withTempDir((dir) => {
+      const entry = path.join(dir, 'nested', 'entry.ts');
+      fs.mkdirSync(path.dirname(entry), { recursive: true });
+      fs.writeFileSync(entry, '// noop');
+
+      expect(resolveGitSha(pathToFileURL(entry).href)).toBeNull();
+    });
+  });
+
   it('formats version line with version + sha when both available', () => {
     withTempDir((dir) => {
       fs.writeFileSync(path.join(dir, 'package.json'), JSON.stringify({ version: '3.3.3' }));
@@ -126,4 +178,10 @@ describe('getCliVersion', () => {
       expect(formatVersionLine(pathToFileURL(entry).href)).toBe('3.3.3 (dddddddd)');
     });
   });
+
+  it('returns a CLI version string', () => {
+    const value = getCliVersion();
+    expect(typeof value).toBe('string');
+    expect(value.length).toBeGreaterThan(0);
+  });
 });
diff --git a/vitest.config.ts b/vitest.config.ts
index a2db739..ab6c83c 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -11,10 +11,10 @@ export default defineConfig({
       include: ['src/**/*.ts'],
       exclude: ['src/index.ts'],
       thresholds: {
-        statements: 70,
-        branches: 70,
-        functions: 70,
-        lines: 70,
+        statements: 90,
+        branches: 80,
+        functions: 90,
+        lines: 90,
       },
     },
   },