diff --git a/CHANGELOG.md b/CHANGELOG.md
index fc9b97b..64af7d6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Changelog
 
-## 0.4.2 — Unreleased
+## 0.5.0 — 2026-01-01
 
 ### Added
 - `likes` command to list your liked tweets (thanks @swairshah).
@@ -15,6 +15,7 @@
 - Cookie extraction timeout is now configurable (default 30s on macOS) via `--cookie-timeout` / `BIRD_COOKIE_TIMEOUT_MS` (thanks @tylerseymour).
 - Search now paginates beyond 20 results when using `-n` (thanks @ryanh-ai).
 - Library exports are now separated from the CLI entrypoint for easier embedding.
+
 ## 0.4.1 — 2025-12-31
 
 ### Added
diff --git a/package.json b/package.json
index feedfc1..0ff8fd2 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@steipete/bird",
-  "version": "0.4.1",
+  "version": "0.5.0",
   "description": "CLI tool for tweeting and replying via Twitter/X GraphQL API",
   "type": "module",
   "main": "dist/index.js",
diff --git a/src/lib/twitter-client-base.ts b/src/lib/twitter-client-base.ts
index fed9250..9b9f7c8 100644
--- a/src/lib/twitter-client-base.ts
+++ b/src/lib/twitter-client-base.ts
@@ -4,8 +4,13 @@ import { type OperationName, QUERY_IDS, TARGET_QUERY_ID_OPERATIONS } from './twi
 import type { CurrentUserResult, TwitterClientOptions } from './twitter-client-types.js';
 import { normalizeQuoteDepth } from './twitter-client-utils.js';
 
-export type Constructor<T = object> = new (...args: unknown[]) => T;
-export type AbstractConstructor<T = object> = abstract new (...args: unknown[]) => T;
+// biome-ignore lint/suspicious/noExplicitAny: TS mixin base constructor requirement.
+export type Constructor<T = object> = new (...args: any[]) => T;
+// biome-ignore lint/suspicious/noExplicitAny: TS mixin base constructor requirement.
+export type AbstractConstructor<T = object> = abstract new (...args: any[]) => T;
+export type Mixin<TBase extends AbstractConstructor<TwitterClientBase>, TAdded> = abstract new (
+  ...args: ConstructorParameters<TBase>
+) => TwitterClientBase & TAdded;
 
 export abstract class TwitterClientBase {
   protected authToken: string;
diff --git a/src/lib/twitter-client-media.ts b/src/lib/twitter-client-media.ts
index ef3e0e4..bb2afcd 100644
--- a/src/lib/twitter-client-media.ts
+++ b/src/lib/twitter-client-media.ts
@@ -1,9 +1,20 @@
-import type { AbstractConstructor, TwitterClientBase } from './twitter-client-base.js';
+import type { AbstractConstructor, Mixin, TwitterClientBase } from './twitter-client-base.js';
 import { TWITTER_MEDIA_METADATA_URL, TWITTER_UPLOAD_URL } from './twitter-client-constants.js';
 import type { UploadMediaResult } from './twitter-client-types.js';
 
-export function withMedia<TBase extends AbstractConstructor<TwitterClientBase>>(Base: TBase) {
-  return class extends Base {
+export interface TwitterClientMediaMethods {
+  uploadMedia(input: { data: Uint8Array; mimeType: string; alt?: string }): Promise<UploadMediaResult>;
+}
+
+export function withMedia<TBase extends AbstractConstructor<TwitterClientBase>>(
+  Base: TBase,
+): Mixin<TBase, TwitterClientMediaMethods> {
+  abstract class TwitterClientMedia extends Base {
+    // biome-ignore lint/complexity/noUselessConstructor lint/suspicious/noExplicitAny: TS mixin constructor requirement.
+    constructor(...args: any[]) {
+      super(...args);
+    }
+
     private mediaCategoryForMime(mimeType: string): string | null {
       if (mimeType.startsWith('image/')) {
         if (mimeType === 'image/gif') {
@@ -162,5 +173,7 @@ export function withMedia<TBase extends AbstractConstructor<TwitterClientBase>>(
         return { success: false, error: error instanceof Error ? error.message : String(error) };
       }
     }
-  };
+  }
+
+  return TwitterClientMedia;
 }
diff --git a/src/lib/twitter-client-posting.ts b/src/lib/twitter-client-posting.ts
index c64d8d9..693ffe6 100644
--- a/src/lib/twitter-client-posting.ts
+++ b/src/lib/twitter-client-posting.ts
@@ -1,10 +1,22 @@
-import type { AbstractConstructor, TwitterClientBase } from './twitter-client-base.js';
+import type { AbstractConstructor, Mixin, TwitterClientBase } from './twitter-client-base.js';
 import { TWITTER_API_BASE, TWITTER_GRAPHQL_POST_URL, TWITTER_STATUS_UPDATE_URL } from './twitter-client-constants.js';
 import { buildTweetCreateFeatures } from './twitter-client-features.js';
 import type { CreateTweetResponse, TweetResult } from './twitter-client-types.js';
 
-export function withPosting<TBase extends AbstractConstructor<TwitterClientBase>>(Base: TBase) {
-  return class extends Base {
+export interface TwitterClientPostingMethods {
+  tweet(text: string, mediaIds?: string[]): Promise<TweetResult>;
+  reply(text: string, replyToTweetId: string, mediaIds?: string[]): Promise<TweetResult>;
+}
+
+export function withPosting<TBase extends AbstractConstructor<TwitterClientBase>>(
+  Base: TBase,
+): Mixin<TBase, TwitterClientPostingMethods> {
+  abstract class TwitterClientPosting extends Base {
+    // biome-ignore lint/complexity/noUselessConstructor lint/suspicious/noExplicitAny: TS mixin constructor requirement.
+    constructor(...args: any[]) {
+      super(...args);
+    }
+
     /**
      * Post a new tweet
      */
@@ -269,5 +281,7 @@ export function withPosting<TBase extends AbstractConstructor<TwitterClientBase>
         error: `${this.formatErrors(errors)} | fallback: ${fallback.error ?? 'Unknown error'}`,
       };
     }
-  };
+  }
+
+  return TwitterClientPosting;
 }
diff --git a/src/lib/twitter-client-search.ts b/src/lib/twitter-client-search.ts
index df122c3..d7ae437 100644
--- a/src/lib/twitter-client-search.ts
+++ b/src/lib/twitter-client-search.ts
@@ -1,11 +1,22 @@
-import type { AbstractConstructor, TwitterClientBase } from './twitter-client-base.js';
+import type { AbstractConstructor, Mixin, TwitterClientBase } from './twitter-client-base.js';
 import { TWITTER_API_BASE } from './twitter-client-constants.js';
 import { buildSearchFeatures } from './twitter-client-features.js';
 import type { SearchResult, TweetData } from './twitter-client-types.js';
 import { extractCursorFromInstructions, parseTweetsFromInstructions } from './twitter-client-utils.js';
 
-export function withSearch<TBase extends AbstractConstructor<TwitterClientBase>>(Base: TBase) {
-  return class extends Base {
+export interface TwitterClientSearchMethods {
+  search(query: string, count?: number): Promise<SearchResult>;
+}
+
+export function withSearch<TBase extends AbstractConstructor<TwitterClientBase>>(
+  Base: TBase,
+): Mixin<TBase, TwitterClientSearchMethods> {
+  abstract class TwitterClientSearch extends Base {
+    // biome-ignore lint/complexity/noUselessConstructor lint/suspicious/noExplicitAny: TS mixin constructor requirement.
+    constructor(...args: any[]) {
+      super(...args);
+    }
+
     /**
      * Search for tweets matching a query
      */
@@ -156,5 +167,7 @@ export function withSearch<TBase extends AbstractConstructor<TwitterClientBase>>
 
       return { success: true, tweets };
     }
-  };
+  }
+
+  return TwitterClientSearch;
 }
diff --git a/src/lib/twitter-client-timelines.ts b/src/lib/twitter-client-timelines.ts
index a29ad51..1cc7bb2 100644
--- a/src/lib/twitter-client-timelines.ts
+++ b/src/lib/twitter-client-timelines.ts
@@ -1,11 +1,24 @@
-import type { AbstractConstructor, TwitterClientBase } from './twitter-client-base.js';
+import type { AbstractConstructor, Mixin, TwitterClientBase } from './twitter-client-base.js';
 import { TWITTER_API_BASE } from './twitter-client-constants.js';
 import { buildBookmarksFeatures, buildLikesFeatures } from './twitter-client-features.js';
-import type { SearchResult } from './twitter-client-types.js';
+import type { GraphqlTweetResult, SearchResult } from './twitter-client-types.js';
 import { parseTweetsFromInstructions } from './twitter-client-utils.js';
 
-export function withTimelines<TBase extends AbstractConstructor<TwitterClientBase>>(Base: TBase) {
-  return class extends Base {
+export interface TwitterClientTimelineMethods {
+  getBookmarks(count?: number): Promise<SearchResult>;
+  getLikes(count?: number): Promise<SearchResult>;
+  getBookmarkFolderTimeline(folderId: string, count?: number): Promise<SearchResult>;
+}
+
+export function withTimelines<TBase extends AbstractConstructor<TwitterClientBase>>(
+  Base: TBase,
+): Mixin<TBase, TwitterClientTimelineMethods> {
+  abstract class TwitterClientTimelines extends Base {
+    // biome-ignore lint/complexity/noUselessConstructor lint/suspicious/noExplicitAny: TS mixin constructor requirement.
+    constructor(...args: any[]) {
+      super(...args);
+    }
+
     private async getBookmarksQueryIds(): Promise<string[]> {
       const primary = await this.getQueryId('Bookmarks');
       return Array.from(new Set([primary, 'RV1g3b8n_SGOHwkqKYSCFw', 'tmd4ifV8RHltzn8ymGg1aw']));
@@ -74,7 +87,7 @@ export function withTimelines<TBase extends AbstractConstructor<TwitterClientBas
                         content?: {
                           itemContent?: {
                             tweet_results?: {
-                              result?: unknown;
+                              result?: GraphqlTweetResult;
                             };
                           };
                         };
@@ -180,7 +193,7 @@ export function withTimelines<TBase extends AbstractConstructor<TwitterClientBas
                             content?: {
                               itemContent?: {
                                 tweet_results?: {
-                                  result?: unknown;
+                                  result?: GraphqlTweetResult;
                                 };
                               };
                             };
@@ -283,7 +296,7 @@ export function withTimelines<TBase extends AbstractConstructor<TwitterClientBas
                         content?: {
                           itemContent?: {
                             tweet_results?: {
-                              result?: unknown;
+                              result?: GraphqlTweetResult;
                             };
                           };
                         };
@@ -333,5 +346,7 @@ export function withTimelines<TBase extends AbstractConstructor<TwitterClientBas
 
       return { success: false, error: firstAttempt.error };
     }
-  };
+  }
+
+  return TwitterClientTimelines;
 }
diff --git a/src/lib/twitter-client-tweet-detail.ts b/src/lib/twitter-client-tweet-detail.ts
index 366e806..5878955 100644
--- a/src/lib/twitter-client-tweet-detail.ts
+++ b/src/lib/twitter-client-tweet-detail.ts
@@ -1,4 +1,4 @@
-import type { AbstractConstructor, TwitterClientBase } from './twitter-client-base.js';
+import type { AbstractConstructor, Mixin, TwitterClientBase } from './twitter-client-base.js';
 import { TWITTER_API_BASE } from './twitter-client-constants.js';
 import { buildArticleFeatures, buildArticleFieldToggles, buildTweetDetailFeatures } from './twitter-client-features.js';
 import type { GetTweetResult, GraphqlTweetResult, SearchResult } from './twitter-client-types.js';
@@ -10,8 +10,21 @@ import {
   parseTweetsFromInstructions,
 } from './twitter-client-utils.js';
 
-export function withTweetDetails<TBase extends AbstractConstructor<TwitterClientBase>>(Base: TBase) {
-  return class extends Base {
+export interface TwitterClientTweetDetailMethods {
+  getTweet(tweetId: string): Promise<GetTweetResult>;
+  getReplies(tweetId: string): Promise<SearchResult>;
+  getThread(tweetId: string): Promise<SearchResult>;
+}
+
+export function withTweetDetails<TBase extends AbstractConstructor<TwitterClientBase>>(
+  Base: TBase,
+): Mixin<TBase, TwitterClientTweetDetailMethods> {
+  abstract class TwitterClientTweetDetails extends Base {
+    // biome-ignore lint/complexity/noUselessConstructor lint/suspicious/noExplicitAny: TS mixin constructor requirement.
+    constructor(...args: any[]) {
+      super(...args);
+    }
+
     private async fetchUserArticlePlainText(
       userId: string,
       tweetId: string,
@@ -318,5 +331,7 @@ export function withTweetDetails<TBase extends AbstractConstructor<TwitterClient
 
       return { success: true, tweets: thread };
     }
-  };
+  }
+
+  return TwitterClientTweetDetails;
 }
diff --git a/src/lib/twitter-client-users.ts b/src/lib/twitter-client-users.ts
index 2cc6d54..8b5da4d 100644
--- a/src/lib/twitter-client-users.ts
+++ b/src/lib/twitter-client-users.ts
@@ -1,4 +1,4 @@
-import type { AbstractConstructor, TwitterClientBase } from './twitter-client-base.js';
+import type { AbstractConstructor, Mixin, TwitterClientBase } from './twitter-client-base.js';
 import {
   SETTINGS_NAME_REGEX,
   SETTINGS_SCREEN_NAME_REGEX,
@@ -9,8 +9,21 @@ import { buildFollowingFeatures } from './twitter-client-features.js';
 import type { CurrentUserResult, FollowingResult } from './twitter-client-types.js';
 import { parseUsersFromInstructions } from './twitter-client-utils.js';
 
-export function withUsers<TBase extends AbstractConstructor<TwitterClientBase>>(Base: TBase) {
-  return class extends Base {
+export interface TwitterClientUserMethods {
+  getCurrentUser(): Promise<CurrentUserResult>;
+  getFollowing(userId: string, count?: number): Promise<FollowingResult>;
+  getFollowers(userId: string, count?: number): Promise<FollowingResult>;
+}
+
+export function withUsers<TBase extends AbstractConstructor<TwitterClientBase>>(
+  Base: TBase,
+): Mixin<TBase, TwitterClientUserMethods> {
+  abstract class TwitterClientUsers extends Base {
+    // biome-ignore lint/complexity/noUselessConstructor lint/suspicious/noExplicitAny: TS mixin constructor requirement.
+    constructor(...args: any[]) {
+      super(...args);
+    }
+
     private async getFollowingQueryIds(): Promise<string[]> {
       const primary = await this.getQueryId('Following');
       return Array.from(new Set([primary, 'BEkNpEt5pNETESoqMsTEGA']));
@@ -326,5 +339,7 @@ export function withUsers<TBase extends AbstractConstructor<TwitterClientBase>>(
 
       return { success: false, error: firstAttempt.error };
     }
-  };
+  }
+
+  return TwitterClientUsers;
 }
diff --git a/src/lib/twitter-client.ts b/src/lib/twitter-client.ts
index 8acea24..70275fc 100644
--- a/src/lib/twitter-client.ts
+++ b/src/lib/twitter-client.ts
@@ -1,14 +1,23 @@
+import type { AbstractConstructor } from './twitter-client-base.js';
 import { TwitterClientBase } from './twitter-client-base.js';
-import { withMedia } from './twitter-client-media.js';
-import { withPosting } from './twitter-client-posting.js';
-import { withSearch } from './twitter-client-search.js';
-import { withTimelines } from './twitter-client-timelines.js';
-import { withTweetDetails } from './twitter-client-tweet-detail.js';
-import { withUsers } from './twitter-client-users.js';
+import { type TwitterClientMediaMethods, withMedia } from './twitter-client-media.js';
+import { type TwitterClientPostingMethods, withPosting } from './twitter-client-posting.js';
+import { type TwitterClientSearchMethods, withSearch } from './twitter-client-search.js';
+import { type TwitterClientTimelineMethods, withTimelines } from './twitter-client-timelines.js';
+import { type TwitterClientTweetDetailMethods, withTweetDetails } from './twitter-client-tweet-detail.js';
+import { type TwitterClientUserMethods, withUsers } from './twitter-client-users.js';
+
+type TwitterClientInstance = TwitterClientBase &
+  TwitterClientMediaMethods &
+  TwitterClientPostingMethods &
+  TwitterClientSearchMethods &
+  TwitterClientTimelineMethods &
+  TwitterClientTweetDetailMethods &
+  TwitterClientUserMethods;
 
 const MixedTwitterClient = withUsers(
   withTimelines(withSearch(withTweetDetails(withPosting(withMedia(TwitterClientBase))))),
-);
+) as AbstractConstructor<TwitterClientInstance>;
 
 export class TwitterClient extends MixedTwitterClient {}