Zn Gate MCP server

zn-gate

Use AI coding agents without exposing your secrets, your data or your systems. An open-source security layer that runs on your machine, between your agent and the tools and content it touches.

Docs · npm package · Python package · Security · Discord

For: developers using Claude Code, Codex CLI, Cursor, OpenCode or any MCP client, and teams building agents with MCP, LangChain, CrewAI or LlamaIndex.

What it does: keeps secret values out of what your agent sends to its model, checks what your agent reads and calls for prompt injection, and audits prompts, skills and configs. Everything runs on your machine, is MIT-licensed and needs no account. The Python package has no runtime dependencies; the npm package's only one is age-encryption (with its @noble/@scure dependencies) for the secret vault, bundled in the package.

Install

Keep secrets out of your agent's context. The secrets scrubber and broker for coding agents keeps real values in an encrypted vault on your machine, and your agent works with markers such as ZNSTRIPEKEY.

npm install -g zn-gate             # Node.js 18+
zn unlock                          # create or unlock the local vault
zn env shadow .env                 # move .env values into the vault, leave markers
zn hooks install claude-code       # or: codex, cursor, opencode

Cursor support is partial: zn-gate can only rewrite the output of MCP tools there, not of shell commands or file reads.

Five-minute walkthrough: docs/secrets.md. What each agent supports: docs/compat.md. Limits: docs/threat-model.md.

Add zn-gate as an MCP server. Pick your agent. Each command adds zn-gate as an MCP server (Node.js 18+).

Claude Code

claude mcp add zn-gate -- npx -y zn-gate mcp

Codex CLI

codex mcp add zn-gate -- npx -y zn-gate mcp

Cursor: add to ~/.cursor/mcp.json

{ "mcpServers": { "zn-gate": { "command": "npx", "args": ["-y", "zn-gate", "mcp"] } } }

OpenCode: add to ~/.config/opencode/opencode.json

{ "mcp": { "zn-gate": { "type": "local", "command": ["npx", "-y", "zn-gate", "mcp"], "enabled": true } } }

Shortened. The full README is on GitHub.