Proxy MCP Server

Transport bridging between stdio and SSE for cross-environment server communication.

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602,682PythonMIT

Overview

The Proxy MCP Server serves as an intermediary to convert between different Model Context Protocol transport layers. It enables users to bridge stdio and SSE/StreamableHTTP connections, specifically allowing clients like Claude Desktop to interface with remote servers that otherwise lack native SSE support. Installation options include PyPI, cloning the GitHub repository, or using pre-built container images. The server is highly configurable via command-line arguments or configuration files, supporting specific transport enforcement for Streamable HTTP environments.

Our verdict

With a security score of 50/100, this tool carries a high risk level for production deployments. The primary concerns stem from the fact that it is a community-maintained project rather than vendor-supported, and its authentication and OAuth mechanisms have not yet undergone an editorial security review. It is best suited for local experimental workflows where transport compatibility is the primary requirement.

  • Supports multiple transport modes including stdio and SSE
  • Zero direct dependencies reduces the total supply-chain surface
  • Includes active development with commits as recent as 3 days ago
  • Authentication methods and OAuth implementations remain unreviewed
  • Not maintained by an official vendor
  • Lack of a dedicated homepage complicates tracking updates

Compatibility

ClientLocalDockerRemoteRead-only
ChatGPT
Claude Desktop
Cursor
VS Code
Windsurf

Frequently asked questions

What are the two primary modes of operation for mcp-proxy?

The server supports stdio-to-SSE/StreamableHTTP conversion and SSE-to-stdio conversion.

How do I use Streamable HTTP transport when connecting to an SSE server?

You must explicitly pass the --transport=streamablehttp argument to the mcp-proxy command.

Can I authenticate with a remote MCP server using mcp-proxy?

Yes, you can provide authentication headers via the --headers argument or the API_ACCESS_TOKEN environment variable. You may also use OAuth2 by providing a client ID, client secret, and token URL.

How do I configure the local stdio server command in SSE-to-stdio mode?

The command line arguments for the local stdio server must be passed after a -- separator following the mcp-proxy arguments.

Is it possible to pass environment variables to a local stdio server?

Yes, you can use the --env argument when running in SSE-to-stdio mode to pass necessary environment variables to the local server.

Changelog

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Proxy MCP Server security score, rated on RepoAI

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