API Reference barrel_mcp v#3.0.0

Main API module for barrel_mcp.

Multi-server tool aggregator for agent hosts.

barrel_mcp application module.

Authentication behaviour and utilities for barrel_mcp.

API key authentication provider for barrel_mcp.

Basic HTTP authentication provider for barrel_mcp.

Bearer token authentication provider for barrel_mcp.

Custom authentication provider for barrel_mcp.

No authentication provider for barrel_mcp.

MCP client for connecting to external MCP servers.

Authorization behaviour for barrel_mcp_client.

Static bearer-token auth for barrel_mcp_client.

OAuth 2.1 + PKCE authorization for barrel_mcp_client.

Persistence for what an OAuth client handle learns: the client it registered (or was given) and the tokens it holds.

Behaviour for handling server-initiated MCP messages.

Default no-op handler for barrel_mcp_client.

Streamable HTTP transport for barrel_mcp_client.

One supervisor per client, holding that client's restart budget so a client that cannot come back exhausts its own budget and nobody else's.

stdio transport for barrel_mcp_client.

Supervisor of the client shells.

Transport behaviour for barrel_mcp_client.

Federation registry for connected MCP clients.

Per-request context.

Elicitation requests, in both modes, and the registry behind URL mode.

MCP request metadata headers (2026-07-28).

Simple HTTP transport for MCP (POST/OPTIONS, no sessions/SSE).

Transport-neutral MCP HTTP engine.

Built-in HTTP/1.1 + HTTP/2 server for the MCP HTTP transports.

MCP Streamable HTTP Transport (protocol 2025-03-26 through 2026-07-28).

JSON Schema 2020-12 validator.

The little JOSE the OAuth client needs: signing a JWT with ES256, RS256 or HS256, a P-256 key as a JWK, and its RFC 7638 thumbprint. Used for private_key_jwt client assertions (RFC 7523) and DPoP proofs (RFC 9449).

Supervisor for HTTP listeners.

Cursor-based pagination walker for MCP */list methods.

The MCP protocol core: JSON-RPC envelopes in, envelopes out.

Handler registry for MCP tools, resources, and prompts.

Opaque, integrity-protected request state for MRTR.

JSON Schema validation for MCP tool inputs and outputs.

Legacy-era sessions and everything that hangs off them.

stdio transport for MCP protocol.

Long-lived notification streams (MCP 2026-07-28).

barrel_mcp top level supervisor.

The process a task-supporting tool reports to while it is not yet known whether its call is answered synchronously or as a task.

Long-running operation registry (MCP tasks).

Translators between MCP tool shapes and LLM provider tool shapes (Anthropic Messages API, OpenAI Chat Completions / Responses).

Minimal RFC 6570 Level-1 URI Template matcher and expander.

Protocol revision comparison.