passmcp — Claude Code MCP server: what it does, how to install
Runs diagnostics on other MCP endpoints and checks their attestations directly inside your editor. Operates read-only and requires an allowlist.
claude mcp add --env PASSMCP_SERVER_ALLOW=<PASSMCP_SERVER_ALLOW> --transport stdio passmcp -- docker run -i --rm -e PASSMCP_SERVER_ALLOW ghcr.io/sebastienrousseau/passmcp-server:0.0.8What passmcp does
This server brings Model Context Protocol diagnostic utilities directly to the coding agent. It exposes commands such as passmcp_check to score another endpoint and passmcp_verify_attestation to validate its assertions. The process communicates over stdio. It never handles credentials and blocks any destination missing from the configured allowlist.
Running passmcp_check fails if the standalone passmcp executable is missing from PATH or not supplied via --passmcp. The official Docker image packages both binaries together. If you test containers across Docker networks, configure PASSMCP_SERVER_ALLOW accordingly.
What it helps with
- audit an MCP endpoint from inside the development agent
- validate signed attestations of external tools
- restrict diagnostic network targets using an allowlist
Example prompts for the agent
- Run a diagnostic check on the target MCP endpoint using passmcp_check.
- Verify the attestation record with passmcp_verify_attestation.
How to install passmcp
Platform CLI
claude mcp add --env PASSMCP_SERVER_ALLOW=<PASSMCP_SERVER_ALLOW> --transport stdio passmcp -- docker run -i --rm -e PASSMCP_SERVER_ALLOW ghcr.io/sebastienrousseau/passmcp-server:0.0.8Replace <…> with your own values
Platform CLI
codex mcp add passmcp --env PASSMCP_SERVER_ALLOW=<PASSMCP_SERVER_ALLOW> -- docker run -i --rm -e PASSMCP_SERVER_ALLOW ghcr.io/sebastienrousseau/passmcp-server:0.0.8Replace <…> with your own values
Config file
{
"mcpServers": {
"passmcp": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"-e",
"PASSMCP_SERVER_ALLOW",
"ghcr.io/sebastienrousseau/passmcp-server:0.0.8"
],
"env": {
"PASSMCP_SERVER_ALLOW": "<PASSMCP_SERVER_ALLOW>"
}
}
}
}Replace <…> with your own values
Config file
{
"servers": {
"passmcp": {
"type": "stdio",
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"-e",
"PASSMCP_SERVER_ALLOW",
"ghcr.io/sebastienrousseau/passmcp-server:0.0.8"
],
"env": {
"PASSMCP_SERVER_ALLOW": "<PASSMCP_SERVER_ALLOW>"
}
}
}
}Replace <…> with your own values
Platform CLI
gemini mcp add -e PASSMCP_SERVER_ALLOW=<PASSMCP_SERVER_ALLOW> passmcp docker run -i --rm -e PASSMCP_SERVER_ALLOW ghcr.io/sebastienrousseau/passmcp-server:0.0.8Replace <…> with your own values
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 passmcp
How to install passmcp in Claude Code?
Run `claude mcp add --env PASSMCP_SERVER_ALLOW=<PASSMCP_SERVER_ALLOW> --transport stdio passmcp -- docker run -i --rm -e PASSMCP_SERVER_ALLOW ghcr.io/sebastienrousseau/passmcp-server:0.0.8`. Replace the placeholder with your target host pattern.
What does passmcp do?
It grants agents read-only inspection tools to evaluate MCP servers and verify their compliance attestations over stdio.
Does passmcp-server require an external binary?
The passmcp_check tool depends on the passmcp CLI tool being present in PATH or configured via --passmcp. In contrast, passmcp_verify_attestation works without external dependencies.
