hf-mcp-server packages

Quick Guide

This repo contains:

• (/mcp) MCP Implementations of Hub API and Search endpoints for integration with MCP Servers.
• (/app) An MCP Server and Web Application for deploying endpoints.

MCP Server

The following transports are supported:

• STDIO
• SSE (To be deprecated, but still commonly deployed).
• StreamableHTTP
• StreamableHTTP in Stateless JSON Mode (StreamableHTTPJson)

The Web Application and HTTP Transports start by default on Port 3000.

SSE and StreamableHTTP services are available at /sse and /mcp respectively. Although though not strictly enforced by the specification this is common convention.

[!TIP] The Web Application allows you to switch tools on and off. For STDIO, SSE and StreamableHTTP this will send a ToolListChangedNotification to the MCP Client. In StreamableHTTPJSON mode the tool will not be listed when the client next requests the tool lists.

Development

This project uses pnpm for build and development.

pnpm run clean -> clean build artifacts

pnpm run build -> build packages

pnpm run start -> start the mcp server application

pnpm run buildrun -> clean, build and start

pnpm run dev -> concurrently watch mcp and start dev server with HMR

Docker Build

Build the image:

docker build -t hf-mcp-server .

Run with default settings (Streaming HTTP JSON Mode), Dashboard on Port 3000:

docker run --rm -p 3000:3000 -e DEFAULT_HF_TOKEN=hf_xxx hf-mcp-server

Run STDIO MCP Server:

docker run -i --rm -e TRANSPORT=stdio -p 3000:3000 -e DEFAULT_HF_TOKEN=hf_xxx hf-mcp-server

TRANSPORT can be stdio, sse, streamingHttp or streamingHttpJson (default).

Transport Endpoints

The different transport types use the following endpoints:

• SSE: /sse (with message endpoint at /message)
• Streamable HTTP: /mcp (regular or JSON mode)
• STDIO: Uses stdin/stdout directly, no HTTP endpoint

Stateful Connection Management

The sse and streamingHttp transports are both stateful - they maintain a connection with the MCP Client through an SSE connection. When using these transports, the following configuration options take effect:

Environment Variable	Default	Description
MCP_CLIENT_HEARTBEAT_INTERVAL	30000ms	How often to check SSE connection health
MCP_CLIENT_CONNECTION_CHECK	90000ms	How often to check for stale sessions
MCP_CLIENT_CONNECTION_TIMEOUT	300000ms	Remove sessions inactive for this duration
MCP_PING_ENABLED	true	Enable ping keep-alive for sessions
MCP_PING_INTERVAL	30000ms	Interval between ping cycles

Environment Variables

The server respects the following environment variables:

• TRANSPORT: The transport type to use (stdio, sse, streamableHttp, or streamableHttpJson)
• DEFAULT_HF_TOKEN: ⚠️ Requests are serviced with the HF_TOKEN received in the Authorization: Bearer header. The DEFAULT_HF_TOKEN is used if no header was sent. Only set this in Development / Test environments or for local STDIO Deployments. ⚠️
• If running with stdio transport, HF_TOKEN is used if DEFAULT_HF_TOKEN is not set.
• HF_API_TIMEOUT: Timeout for Hugging Face API requests in milliseconds (default: 12500ms / 12.5 seconds)
• USER_CONFIG_API: URL to use for User settings (defaults to Local front-end)
• MCP_STRICT_COMPLIANCE: set to True for GET 405 rejects in JSON Mode (default serves a welcome page).