AT Protocol

An MCP server for reading public data from the AT Protocol network without authentication.

Operates at the abstract repo/collection/record level rather than exposing Bluesky-specific APIs, so it works with any data stored on any AT Protocol PDS. Also includes Bluesky search as a convenience.

Tools

Tool	Description
resolve_handle	Resolve an AT Protocol handle to its DID
describe_repo	Get repository metadata: handle, DID, DID document, and available collections
list_records	List records in a collection with pagination and reverse ordering
get_record	Fetch a single record by repo, collection NSID, and record key
get_blob	Fetch a blob by repo and CID — returns images as inline MCP image content
search_posts	Full-text search for posts (via Bluesky AppView)
search_actors	Search for users by name or handle (via Bluesky AppView)

How it works

The server resolves each identity's PDS dynamically through the AT Protocol identity layer, then sends XRPC requests directly to that PDS. This means it correctly handles users on any PDS, not just those hosted by Bluesky.

Client ──MCP──▶ atproto-mcp
                    │
                    ├── resolve identity ──▶ slingshot.microcosm.blue
                    │       (handle/DID → PDS URL)
                    │
                    ├── repo operations ──▶ user's actual PDS
                    │       (describeRepo, listRecords, getRecord, getBlob)
                    │
                    └── search ──▶ public.api.bsky.app
                            (searchPosts, searchActors)

Building

Requires Rust 1.85+ (edition 2024).

cargo build --release

The binary is at target/release/atproto-mcp.

Usage

The server communicates over stdio using the Model Context Protocol. Add it to your MCP client configuration:

{
  "mcpServers": {
    "atproto": {
      "command": "/path/to/atproto-mcp"
    }
  }
}

Examples

Browse a user's collections:

Call describe_repo with {"repo": "karashiiro.moe"} to see all collections in their repository.

Read posts:

Call list_records with {"repo": "alice.bsky.social", "collection": "app.bsky.feed.post", "limit": 10} to list their recent posts.

Fetch a specific record:

Call get_record with {"repo": "alice.bsky.social", "collection": "app.bsky.actor.profile", "rkey": "self"} to read their profile record.

Fetch an image:

Find an image CID from a post record's embed, then call get_blob with {"repo": "alice.bsky.social", "cid": "bafkrei..."}.

Dependencies

• rmcp — Rust MCP SDK
• jacquard — AT Protocol client SDK
• slingshot — Identity resolution service (for PDS discovery)