generated: '2026-09-13'
method: probed
source: https://buf.build/docs/bsr/apis/mcp/
status: live-auth-gated
server:
  name: bsr
  vendor: Buf Technologies, Inc.
  transport: http
  url: https://buf.build/mcp
  private_instance_url: https://<your-bsr-instance>/mcp
  description: >-
    The Buf Schema Registry exposes its public v1 Registry API as MCP tools so an agent
    can find a module, fetch its schema, and inspect commits and labels without a
    generated client. Buf's own docs state the token an approved client receives "has the
    same access as the user who approved it, so any RPC you can call from the web UI or
    the Buf CLI is callable through MCP, including writes."
deployment:
  mode: remote
  endpoint: https://buf.build/mcp
  auth: oauth
  verified: probed
  checked: '2026-09-13'
  probe:
    - url: https://buf.build/mcp
      method: 'POST tools/list (jsonrpc 2.0, anonymous)'
      status: 401
      body: 'no bearer token'
    - url: https://api.buf.build/mcp
      method: 'POST tools/list (jsonrpc 2.0, anonymous)'
      status: 401
      www_authenticate: >-
        Bearer resource_metadata="https://buf.build/.well-known/oauth-protected-resource/mcp",
        scope="mcp"
  note: >-
    A prior round recorded the endpoint as https://api.buf.build/mcp. Both hosts answer
    the MCP path, but https://buf.build/mcp is the URL Buf documents, and it is also the
    `resource` value in the provider's own RFC 9728 protected-resource document, so it is
    recorded here as canonical.
authentication:
  interactive: >-
    Browser OAuth2 with dynamic client registration (RFC 7591) and PKCE S256. First
    connection opens a consent page; the client caches the issued API token.
  headless: >-
    Pre-existing BSR API token passed as `Authorization: Bearer <BUF_TOKEN>`. Documented
    for bots and CI, because the OAuth2 flow requires browser consent.
  scope: mcp
  authorization_server: https://buf.build
  protected_resource_metadata: https://buf.build/.well-known/oauth-protected-resource/mcp
  revocation: >-
    Each authorized client appears as a named API token in account settings; deleting the
    token revokes the client immediately.
clients_documented:
  - name: Claude Code
    install: claude mcp add --transport http bsr https://buf.build/mcp
  - name: Codex
    install: codex mcp add bsr --url https://buf.build/mcp
  - name: OpenCode
    install: 'opencode.json mcp entry {"type":"remote","url":"https://buf.build/mcp"} then opencode mcp auth bsr'
tools_note: >-
  No live tool list captured: anonymous tools/list returns 401 on both hosts, so the real
  inputSchemas require an authenticated introspection run. Buf documents the exposed
  surface as "the BSR Registry API, with the v1 services for modules, owners, commits, and
  labels as MCP tools" and points at the Registry API documentation for the method list.
  The named-but-unschema'd tool surface is mapped against the real .proto RPCs in
  mcp/buf-tool-crosswalk.yml; nothing there is presented as a captured tool definition.
backing_contract: grpc/buf-grpc-index.yml