What can you do with this server?

The ActivityPub MCP Server acts as a Fediverse client for LLMs, enabling exploration and interaction with decentralized social networks (Mastodon, Misskey, Pleroma, etc.) via the Model Context Protocol — read-only by default, with optional write access. Public Read Tools (no account needed) * Discover actors — Look up any Fediverse user profile by handle, retrieving bio, follower/following URLs, and inbox/outbox endpoints * Fetch actor timelines — Retrieve posts from any user's public timeline with pagination * Get post threads — Fetch a post and its full conversation (replies and parent posts) up to configurable depth * Search the Fediverse — Unified search for accounts, posts, or hashtags across any instance * Get trending hashtags/posts — See what's currently trending on a given instance * Get public timelines — Browse an instance's local or federated public timeline * Get instance info — Retrieve detailed metadata about any Fediverse instance * Discover instances — Find instances with filters for software type, language, user count, registration status, and more Authenticated Read Tools (account required) * List and switch between configured accounts * Verify credentials and obtain account information * Get your personalized home timeline * Retrieve notifications (mentions, follows, boosts, favourites) * Access bookmarks and favourited posts * Check relationship status with other accounts (following, blocked, muted, etc.) Write Tools (opt-in via ACTIVITYPUB_ENABLE_WRITES=true) * Post, reply, and delete statuses * Boost, favourite, and bookmark posts * Follow, mute, and block accounts * Vote in polls, upload media, and schedule posts Authentication is handled via OAuth/MiAuth with multi-account support and CLI login. An HTTP transport mode with bearer authentication and a health check endpoint is also available.

Which integrations are available for this server?

Enables interaction with the ActivityPub protocol, allowing discovery and interaction with actors and content across the Fediverse. Provides tools to interact with Mastodon instances, including reading timelines, posting, and managing accounts. Provides tools to interact with Misskey instances, including reading timelines, posting, and managing accounts. Provides tools to interact with Pleroma instances, including reading timelines, posting, and managing accounts.

How do I use ActivityPub MCP Server?

1. Click on "Deploy Server". 2. Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state. 3. In the chat, type @ followed by the MCP server name and your instructions, e.g., "@ActivityPub MCP Server show trending posts on mastodon.social" That's it! The server will respond to your query, and you can continue using it as needed. Here is a step-by-step guide with screenshots.

ActivityPub MCP Server

by cameronrye

Overview Schema Source Related Servers Discussions Admin

TypeScript

Hybrid

Install

Requires Node.js 20+.

npx -y activitypub-mcp

One-click install:

Add to Cursor Install in VS Code

Claude Desktop

One-click: download the .mcpb bundle (activitypub-mcp-<version>.mcpb) from the latest release and open it in Claude Desktop.

Manual: edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "activitypub": {
      "command": "npx",
      "args": ["-y", "activitypub-mcp"]
    }
  }
}

Restart Claude Desktop.

Cursor

Edit ~/.cursor/mcp.json:

{
  "mcpServers": {
    "activitypub": {
      "command": "npx",
      "args": ["-y", "activitypub-mcp"]
    }
  }
}

Restart Cursor.

Related MCP server: Claude-LMStudio Bridge

Read-only by default

Out of the box, only read tools are registered: discover actors, fetch timelines, search, get threads, explore instances, read trending content. No write tools exist in the MCP session, so injected fediverse content cannot trigger account actions.

Public read tools (no account needed): discover-actor, fetch-timeline, get-post-thread, get-instance-info, get-public-timeline, get-trending-hashtags, get-trending-posts, search, discover-instances.

Authenticated read tools (account required): list-accounts, switch-account, verify-account, get-home-timeline, get-notifications, get-bookmarks, get-favourites, get-relationship.

Enabling writes

Set ACTIVITYPUB_ENABLE_WRITES=true in the environment or MCP config env block. This registers the full set of mutation tools: post, reply, delete, boost, favourite, bookmark, follow, mute, block, vote, upload media, and scheduled posts. Read the threat model before enabling.

{
  "mcpServers": {
    "activitypub": {
      "command": "npx",
      "args": ["-y", "activitypub-mcp"],
      "env": {
        "ACTIVITYPUB_ENABLE_WRITES": "true"
      }
    }
  }
}

Authentication

npx activitypub-mcp login mastodon.social

This runs OAuth (Mastodon-family) or MiAuth (Misskey) in your browser and saves credentials to ~/.config/activitypub-mcp/accounts.json. Multi-account is supported — use switch-account to change the active account.

Alternatively, set ACTIVITYPUB_DEFAULT_INSTANCE and ACTIVITYPUB_DEFAULT_TOKEN env vars for a single account without the CLI flow.

Platform support

discover-actor and fetch-timeline speak plain ActivityPub (WebFinger → actor → outbox), so they read any conformant ActivityPub server — Mastodon, Misskey, Foundkey, Pleroma/Akkoma, Lemmy (communities and users), PeerTube (channels and accounts), GoToSocial, and Pixelfed.

The instance-API read tools (search, get-trending-hashtags, get-trending-posts, get-public-timeline) and every write tool require a Mastodon- or Misskey-API instance, since they call those platforms' REST APIs. Login uses OAuth (Mastodon-family) or MiAuth (Misskey).

Example

After adding the server to your MCP client, try:

"Look up @gargron@mastodon.social and summarize their latest posts."

The model will call discover-actor to fetch the profile, then fetch-timeline to read recent posts.

See examples/ for copy-pasteable recipes — Fediverse research digests, scheduled threads, notification triage, image posts with alt text, and topic curation.

HTTP transport

In addition to stdio (default), the server supports HTTP mode with a bearer-gated /mcp endpoint and /health liveness check. Set MCP_HTTP_SECRET (min 16 chars) to enable.

To self-host it as a service, the repo includes a Dockerfile and a docker-compose.yml (HTTP mode):

export MCP_HTTP_SECRET=$(node -e "console.log(require('crypto').randomBytes(32).toString('hex'))")
docker compose up --build   # then: curl http://localhost:8080/health

See the docs for full configuration.

Security

This server fetches world-writable fediverse content — posts, bios, notifications — and feeds it to the LLM. That content can contain prompt-injection payloads. Notifications are an unsolicited channel: anyone can mention your account. The <untrusted-content> envelope and read-only default reduce the risk surface, but do not eliminate it.

See SECURITY.md for the full threat model, SSRF protections, credential handling, and reporting instructions.

Documentation

The full tool reference, resource list, prompt catalog, environment variable guide, and deployment notes live on the docs site:

cameronrye.github.io/activitypub-mcp/docs/

License

MIT — see LICENSE.

Acknowledgments

Built on the Model Context Protocol by Anthropic, and interacts with the decentralized social web as specified by ActivityPub (W3C) and ActivityStreams.

Available Tools

18 tools

discover-actorDiscover Fediverse ActorA

Read-only

Find and retrieve the profile of any fediverse user or account (called an 'actor' in ActivityPub). Returns display name, bio, follower/following URLs, and inbox/outbox endpoints. Pass a handle like '@alice@mastodon.social' or 'alice@mastodon.social'.

Name	Required	Description	Default
`identifier`	Yes	Actor handle in 'user@domain' or '@user@domain' form (e.g., 'alice@mastodon.social')

Output Schema

Name	Required	Description
`actor`	Yes

discover-instancesDiscover Fediverse InstancesA

Read-only

Discover fediverse instances in real-time using the instances.social API with advanced filtering

Name	Required	Description
`software`	No	Filter by software type
`language`	No	Filter by language code (e.g., 'en', 'de', 'ja')
`minUsers`	No	Minimum number of users
`maxUsers`	No	Maximum number of users
`openRegistrations`	No	Only show instances with open registrations
`sortBy`	No	Sort results by field
`sortOrder`	No	Sort order (default: desc)
`limit`	No	Number of results (default: 20)

Output Schema

Name	Required	Description
`instances`	Yes
`hasMore`	No

fetch-timelineFetch Actor TimelineA

Read-only

Fetch recent posts (the outbox) from any fediverse actor — a user or account — with cursor- and ID-based pagination. Pass a handle like 'alice@mastodon.social'.

Name	Required	Description
`identifier`	Yes	Actor identifier (e.g., user@example.social)
`limit`	No	Number of posts to fetch (default: 20)
`cursor`	No	Pagination cursor from previous response to fetch next page
`minId`	No	Return posts newer than this post ID (pagination)
`maxId`	No	Return posts older than this post ID (pagination)
`sinceId`	No	Return posts more recent than this post ID

Output Schema

Name	Required	Description
`posts`	Yes
`nextCursor`	No	Opaque cursor for the next page, if more results
`hasMore`	No
`source`	No	Account/actor/instance the posts came from

get-bookmarksGet BookmarksB

Read-only

Get your bookmarked posts

Name	Required	Description	Default
`limit`	No	Number of posts (default: 20)
`accountId`	No	Account ID

Output Schema

Name	Required	Description
`posts`	Yes
`nextCursor`	No	Opaque cursor for the next page, if more results
`hasMore`	No
`source`	No	Account/actor/instance the posts came from

get-favouritesGet FavouritesA

Read-only

Get posts you have favourited

Name	Required	Description	Default
`limit`	No	Number of posts (default: 20)
`accountId`	No	Account ID

Output Schema

Name	Required	Description
`posts`	Yes
`nextCursor`	No	Opaque cursor for the next page, if more results
`hasMore`	No
`source`	No	Account/actor/instance the posts came from

get-home-timelineGet Home TimelineA

Read-only

Get your personalized home timeline (posts from accounts you follow)

Name	Required	Description
`limit`	No	Number of posts (default: 20)
`maxId`	No	Return posts older than this ID
`sinceId`	No	Return posts newer than this ID
`accountId`	No	Account ID

Output Schema

Name	Required	Description
`posts`	Yes
`nextCursor`	No	Opaque cursor for the next page, if more results
`hasMore`	No
`source`	No	Account/actor/instance the posts came from

get-instance-infoGet Instance InformationA

Read-only

Get detailed information about a fediverse instance: software and version, description, registration policy, supported languages, user/post/domain counts, and contact account.

Name	Required	Description	Default
`domain`	Yes	Instance domain (e.g., example.social)

Output Schema

Name	Required	Description
`domain`	Yes
`title`	No
`description`	No
`version`	No
`software`	No
`users`	No
`registrationsOpen`	No

get-notificationsGet NotificationsC

Read-only

Get your notifications (mentions, follows, boosts, favourites)

Name	Required	Description
`limit`	No	Number of notifications (default: 20)
`types`	No	Filter by notification types
`accountId`	No	Account ID

Output Schema

Name	Required	Description
`notifications`	Yes

get-post-threadGet Post ThreadA

Read-only

Fetch a post and its full conversation thread including replies and parent posts

Name	Required	Description
`postUrl`	Yes	The URL of the post to fetch the thread for
`depth`	No	How many levels of nested replies to fetch (default: 2)
`maxReplies`	No	Maximum number of replies to fetch (default: 50)

Output Schema

Name	Required	Description
`ancestors`	Yes
`post`	Yes
`replies`	Yes

get-public-timelineGet Public TimelineA

Read-only

Fetch an instance's public timeline. scope 'federated' (default) shows posts the instance has seen from across the fediverse; 'local' shows only posts authored on that instance.

Name	Required	Description
`domain`	Yes	Instance domain, e.g. mastodon.social
`scope`	No	default: federated
`limit`	No	Number of posts to fetch (default: 20)
`maxId`	No	Return results older than this ID (for pagination)

Output Schema

Name	Required	Description
`posts`	Yes
`nextCursor`	No	Opaque cursor for the next page, if more results
`hasMore`	No
`source`	No	Account/actor/instance the posts came from

get-relationshipGet RelationshipA

Read-only

Check your relationship status with another account (following, followed by, blocking, muting, etc.). Pass a single acct like 'username@instance'. To check multiple accounts, call this tool once per account.

Name	Required	Description
`acct`	Yes	Account to check relationship with (username@instance). If you have multiple accounts to check, call this tool once per account.
`accountId`	No	Your account ID
`accountIds`	No	Deprecated / not supported. Use 'acct' (a single username@instance string) and call this tool once per account.

Output Schema

Name	Required	Description
`acct`	Yes
`following`	No
`followedBy`	No
`blocking`	No
`muting`	No
`requested`	No

get-scheduled-postsGet Scheduled PostsA

Read-only

List your scheduled posts that haven't been published yet

Name	Required	Description	Default
`limit`	No	Number of posts (default: 20)
`accountId`	No	Account ID

Output Schema

Name	Required	Description
`scheduledPosts`	Yes

get-trending-hashtagsGet Trending HashtagsA

Read-only

Get currently trending hashtags on a fediverse instance (Mastodon-compatible instances that expose a trends API).

Name	Required	Description	Default
`domain`	Yes	Instance domain (e.g., mastodon.social)
`limit`	No	Number of hashtags to fetch (default: 20)

Output Schema

Name	Required	Description
`hashtags`	Yes

get-trending-postsGet Trending PostsA

Read-only

Get currently trending posts on a fediverse instance (Mastodon-compatible instances that expose a trends API).

Name	Required	Description	Default
`domain`	Yes	Instance domain (e.g., mastodon.social)
`limit`	No	Number of posts to fetch (default: 20)

Output Schema

Name	Required	Description
`posts`	Yes
`nextCursor`	No	Opaque cursor for the next page, if more results
`hasMore`	No
`source`	No	Account/actor/instance the posts came from

list-accountsList Configured AccountsA

Read-only

List all configured authenticated accounts for write operations

Name	Required	Description	Default
No parameters

Output Schema

Name	Required	Description
`accounts`	Yes
`writeEnabled`	Yes
`activeAccountId`	No

searchSearch FediverseA

Read-only

Unified search across the fediverse - find accounts, posts, or hashtags on any instance

Name	Required	Description
`query`	Yes	Search query
`domain`	No	Instance domain to search on (default: mastodon.social)
`type`	No	Type of content to search for (default: all)
`limit`	No	Number of results per type (default: 10)

Output Schema

Name	Required	Description
`accounts`	No
`statuses`	No
`hashtags`	No

switch-accountSwitch Active AccountA

Switch the active account used for write operations

Name	Required	Description	Default
`accountId`	Yes	The account ID to switch to (use list-accounts to see IDs)

Output Schema

Name	Required	Description
`accountId`	No
`username`	No
`instance`	No
`active`	No
`verified`	No

verify-accountVerify Account CredentialsB

Read-only

Verify that the account credentials are valid and get account information

Name	Required	Description	Default
`accountId`	No	The account ID to verify (defaults to active account)

Output Schema

Name	Required	Description
`accountId`	No
`username`	No
`instance`	No
`active`	No
`verified`	No

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

18 tool updatesv3.1.4Jun 17, 2026

Changeddiscover-actor1 field changed