MCPProxy — Claude Code MCP server: one endpoint, quarantine, tool
A local proxy in front of every MCP server you run: the agent loads a short list of search tools, and new servers stay quarantined until you approve them.
Open on GitHubWhat MCPProxy does
MCPProxy runs as a local process on macOS, Linux and Windows. The core is one binary with the web UI inside it, so there is no extra service to launch; macOS also gets an optional menu-bar app for start, stop, server health and logs. It federates the MCP servers you connect, which lets you go past client caps such as Cursor's 40-tool limit and the 128-function ceiling in OpenAI.
Instead of the full upstream catalog, the agent sees the proxy's own discovery and execution tools — retrieve_tools, describe_tool and the call_tool_* variants — then fetches schemas when it needs them. Context savings vary with tool count, routing mode and client. On the frozen 45-tool reference corpus the initial proxy menu is actually larger than plain listing, since its own tools have a fixed cost; savings only kick in past the break-even point.
Fresh servers are quarantined and their tools withheld until you review them. Under the default manual trust mode, edits to an approved tool's definition come back for another review. That narrows exposure to Tool Poisoning Attacks but is no safety guarantee. Docker-based scanners — Snyk, Semgrep, Trivy, Cisco — can inspect quarantined servers before approval, and findings are normalised to SARIF with a composite risk score.
What it helps with
- connect many MCP servers without hitting a client tool limit
- vet a new server's tools before the agent can call them
- shrink the tool menu the agent loads at startup
- scan a quarantined server with security tools before approval
- watch MCP activity from the macOS menu-bar app
Example prompts for the agent
- Use
retrieve_toolsto show what the connected servers can do - Approve the quarantined server once I review its tools
- Describe that tool's schema with
describe_toolbefore calling it
How to install MCPProxy
Install
The MCP registry has no launch command for it: see the repository README
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about MCPProxy
How do I install MCPProxy in Claude Code?
Grab the release build for your system: a DMG for macOS (arm64 or amd64) or the setup.exe for Windows (x64 or ARM64). The Windows installer places both the core server and the tray app in Program Files, puts the tool on PATH and adds Start Menu shortcuts.
What does MCPProxy do?
It puts a single local endpoint ahead of all your MCP servers, exposes search and call tools on demand, and keeps new servers quarantined until you sign off.
How much context does it save?
There is no fixed percentage. On the 45-tool reference corpus the proxy's startup menu came out larger than a plain list, so a saving appears only once enough tools are connected — quote the tool count alongside any figure.
