Install GuardRails-MCP in Claude Code

What you need first

• Claude Code, installed.
• uv, which gives the uvx command the server starts with.
• Your own value for YOUR_GUARDRAILS_DATA_DIR.

Steps

1. Run this in a terminal, in the project folder. It adds the server for you in that project; put --scope user after claude mcp add to have it in every project.

claude mcp add --env GUARDRAILS_DATA_DIR=YOUR_GUARDRAILS_DATA_DIR --transport stdio guardrails-mcp -- uvx guardrails-mcp==0.1.1

2. Replace YOUR_GUARDRAILS_DATA_DIR with your own value.
3. Start Claude Code and type /mcp: the server is listed with its state.

Check it worked

Ask Claude Code: List the tools of guardrails-mcp.

If it does not start

spawn uvx ENOENT

uv is not on the PATH that Claude Code sees. Install it, or write the full path of uvx in the config.

The server starts, but its tools fail

A YOUR_… placeholder is still in the config, or its value is wrong.