stonegate

Universal MCP tool gateway for AI agents.

A compiled Rust MCP server that unifies all your MCP backends behind one endpoint. Tool discovery, automatic routing, connection pooling, circuit breakers, crash recovery. Framework-independent and local-first.

Install

brew install thekeystoneproject/tap/stonegate

Or download the binary from keystoneproject.dev.

Quickstart

# Start the server
stonegate serve

# Activate your license key
stonegate activate SG-XXXX-XXXX-XXXX-XXXX

Point any MCP-compatible agent platform at 127.0.0.1:3393. That's it.

Configuration

# ~/.stonegate/config.toml
host = "127.0.0.1"
port = 3393
data_dir = "~/.stonegate"

[[servers]]
name = "filesystem"
command = "npx"
args = ["-y", "@modelcontextprotocol/server-filesystem", "/tmp"]

[[servers]]
name = "github"
command = "npx"
args = ["-y", "@modelcontextprotocol/server-github"]
env = { GITHUB_TOKEN = "ghp_..." }

Environment overrides: STONEGATE_HOST, STONEGATE_PORT, STONEGATE_DATA_DIR.

Features

• Unified tool catalog across all MCP backends
• Automatic routing to the correct server
• Connection pooling — shared backends, no duplicates
• Circuit breaker — failing backends isolated instantly
• Crash recovery — backends auto-restart
• Async dispatch for long-running tools

Works with

Any platform that speaks MCP connects directly:

• Claude Code / Claude Desktop
• Hermes
• CrewAI
• LangGraph
• OpenHands
• Haystack
• Google ADK
• Microsoft Agent Framework

Pricing

	Free	Pro ($19/mo)	Enterprise ($99/mo)
MCP servers	3	Unlimited	Unlimited
Tool discovery	Yes	Yes	Yes
Health monitoring	—	Yes	Yes
Request logging	—	Yes	Yes
Priority dispatch	—	Yes	Yes
Fleet management	—	—	Yes

Get a key at keystoneproject.dev.

Data ownership

Your data stays on your machine. No cloud dependency. No vendor lock-in.

Documentation

Full documentation at keystoneproject.dev/docs.

Stone Suite

stonegate is part of the Stone suite — three compiled Rust MCP servers for AI agent infrastructure:

• stonemem — Institutional memory
• stonemux — Multi-agent coordination
• stonegate — Universal tool gateway (this repo)

License

Proprietary — Copyright (c) 2026 The Keystone Project, Inc. All rights reserved.