getproxykit/proxykit-mcp

**Model Context Protocol server for ProxyKit — drive a local HTTP(S) debugging proxy from Claude, Cursor, and any MCP host.**
proxykit-mcp is a small stdio binary that exposes a running ProxyKit engine to
MCP clients. Every tool call is one HTTP call to the engine's control API on
127.0.0.1 — the server holds no traffic of its own and talks to nothing off
your machine.
> "Mock the checkout endpoint to fail half the time." · "Summarize the last 500
> captured requests against my baseline." · "Add 800 ms of latency to
> /api/payments and replay the session."
>
> Typed into your editor, run against real traffic ProxyKit already captured.
- **Website:** https://proxykit.net
- **Setup guide (all hosts):** https://proxykit.net/mcp
- **CLI reference:** https://proxykit.net/docs
This repository is the public home of the proxykit-mcp server — its docs,
tool reference, and MCP registry metadata. The engine and desktop app are
ProxyKit, a proprietary product with a free tier.
---
Install
The binary ships inside every ProxyKit CLI archive **and** inside the desktop
app. Pick whichever you already have.
With Homebrew (CLI)
That puts proxykit, proxy-engine, and proxykit-mcp on your PATH.
With WinGet (Windows)
From the desktop app
Download from https://proxykit.net/download. The binary is bundled at:
---
Connect an MCP host
The engine writes a control.token file on startup; point the MCP server at
that file — **never paste the token into the config**. Add this to your host's
MCP config (~/.cursor/mcp.json, Claude Desktop's claude_desktop_config.json,
.mcp.json, …):
Start ProxyKit (desktop or proxykit start --headless), restart your MCP host,
and ask it: *"List my latest captured traffic in ProxyKit."*
Per-client paths and one-click install from the desktop app are documented at
**https://proxykit.net/mcp**.
Environment variables
| Variable | Purpose |
|---|---|
| PROXYKIT_CONTROL_AUTH_TOKEN_FILE | Path to the engine's control.token. Preferred over the raw token. |
| PROXYKIT_CONTROL_AUTH_TOKEN | The token directly (use the _FILE form instead where possible). |
| PROXYKIT_MCP_TIER | Comma-separated allowlist: readonly (default), mutate, capture, analysis, replay. |
| PROXYKIT_ENGINE_URL | Engine control API. Defaults to http://127.0.0.1:17171. |
---
Safety model
- **Local only.** The server calls 127.0.0.1:17171. The engine binds loopback
and rejects non-loopback callers.
- **Token-gated.** Every control call carries X-Proxykit-Control-Token. No
token, no access.
- **Least privilege by tier.** readonly is the default and can only read.
Anything that mutates rules, controls capture, or replays traffic is off
until you opt its tier in — so an agent can't create a mock or clear your
capture unless you explicitly allowed that tier.
- **Redacted at the source.** Response bodies are redacted server-side before
they reach the agent.
---
Tools
50 tools across five tiers. readonly is enabled by default; the rest are
opt-in via PROXYKIT_MCP_TIER.
readonly — read state (default)
| Tool | Does |
|---|---|
| proxy_status | Is the proxy running, what port, TLS configured, buffer size |