MCP Compressing Router

Compress all connected MCP into a single router MCP and save up to 99% on
tokens.

Description

MCP Compress Router is a single MCP server for developers who connect several MCP servers to a coding agent. Connected directly, each request carries all of their tool definitions — about 26K tokens for three popular servers, roughly $0.93 over a 50-turn session. The router replaces those listings with two tools, get_tool_schema and invoke_tool, and returns a tool’s full schema only when the agent asks for it. The same three servers compress to a catalog of about 600 tokens, cutting the overhead by roughly 97.7%. See About token overhead for the cost model.

The router helps most in two cases:

• You use more than one coding agent. Connect each agent to the router once and manage every downstream MCP server in one place.
• Your agent loads full tool definitions on every request. The router saves the most where the agent sends every definition on every turn.

The actual savings depend on the coding agent: some agents already keep tool definitions out of their requests with their own algorithms (see Measured savings below).

Prerequisites

• Node.js 24 or later — the router runs on Node.js and is launched via npx, so no separate install step is needed.
• A coding agent that supports stdio MCP servers — opencode, Claude Code, Codex, GitHub Copilot, Cursor, and most other modern agents.

Quick Start

The router is published on npm as mcp-compress-router. You do not need to install it — just run it with npx.

Setup is two steps: connect your coding agent to the router, then add the MCP servers you want to compress.

1. Connect your coding agent

Register the router the same way you register any other stdio MCP server, at the user scope (or your agent’s equivalent). It reads its server list from a user-wide config file, so every project shares one compressed catalog:

opencode mcp add mcp-compress-router -- npx -y mcp-compress-router@latest

See Connect your coding agent for Claude Code, Codex, GitHub Copilot (VS Code), and other agents.

2. Add downstream MCP servers

Use the add command to register each MCP server you want to compress:

npx mcp-compress-router@latest add playwright \
  --description "Browser automation for testing and inspecting web pages." \
  -- npx -y @playwright/mcp

The add command requires a short description so the LLM can tell what the server is and when to use it; a hand-edited config may omit it, and the catalog then skips that description. Use environment variables to keep secrets out of the config:

npx mcp-compress-router@latest add github \
  --description "GitHub API tools for browsing repositories, issues, and pull requests." \
  -e GITHUB_PERSONAL_TOKEN=ghp_xxx \
  -- npx -y @modelcontextprotocol/server-github

HTTP servers, custom headers, OAuth, per-server tool filters, and enable/disable are covered in the configuration reference.

3. Verify and use

Check that everything is wired up:

npx mcp-compress-router@latest list

Then start a new session in your coding agent. The agent picks up the router’s two tools — get_tool_schema and invoke_tool — and uses them to discover and call every server you added, without ever seeing the raw tool listings of each downstream server. get_tool_schema accepts a server name alone to list that server’s tools, or a server and tool names to return their parameter schemas.

Acknowledgements

• mcp2cli — a very similar idea of how MCP can be compressed, but to a CLI.
• mcp-compressor — also a very similar idea; the “two tools” approach was borrowed from this project, though it only compresses a single MCP server.

Measured Savings

Newer coding agents have caught up: Claude Code’s Tool Search, Codex CLI’s code mode, and OpenCode V2’s Code Mode each defer MCP tool definitions on their own, so a current agent already keeps most definitions out of its requests. With one of those agents on its own, you may not need the router for token savings — the table below shows how little it adds there. With several agents, the router remains the single place where every downstream MCP server is connected, configured, and authenticated, no matter how each agent defers tools.

Measured router-vs-direct savings (September 2026; total tokens depend on the session’s turn count, so the per-turn column is the stable signal):

Negative values mean the router used more. Cost figures come from each agent’s own accounting and are approximate. See Benchmarks for the full tables.

Documentation

Using the router

• Configuration reference — every config field, CLI command, and environment variable
• Connect your coding agent
• Authenticate with OAuth
• Connect the GitHub MCP server
• Connect the Figma MCP server
• About token overhead — the problem, the cost model, and the two-tool workflow

Contributing

• Development guide — set up, build, run, and debug from a repository clone
• Benchmarks — harness, measured savings, and how to reproduce a run
• Manual QA — the Compose stack and test plans
• Releasing — releases and canary builds
• About the architecture
• About the process lifecycle
• About development practices
• Changelog
• LLM agent rules