Skillget

urbit-mcp

mcp
Security Audit
Fail
Health Warn
  • License — License: MIT
  • Description — Repository has a description
  • Active repo — Last push 0 days ago
  • Low visibility — Only 5 GitHub stars
Code Fail
  • fs module — File system access in .github/workflows/groundwire-verify.yml
  • rm -rf — Recursive force deletion command in build.sh
Permissions Pass
  • Permissions — No dangerous permissions requested
Purpose
This tool provides a Model Context Protocol (MCP) interface for Urbit, allowing AI assistants and LLMs to interact directly with an Urbit personal server to execute commands, manage desks, and access resources.

Security Assessment
Overall Risk: Medium. The tool requires passing your Urbit ship's authentication cookie directly to the AI provider via command-line arguments or configuration files. While this is necessary for the tool to function and the connection is made over localhost, storing session cookies in plain text (e.g., in `~/.codex/config.toml`) is a security risk. The automated rule-based scan flagged a recursive force deletion command (`rm -rf`) inside `build.sh`. While this is standard for cleaning build directories, users should always inspect shell scripts before executing them. No hardcoded secrets, dangerous application permissions, or external network callbacks were detected in the application code itself.

Quality Assessment
The project is actively maintained, with its most recent push happening today. It uses the permissive and standard MIT license. However, community visibility is currently very low, with only 5 stars on GitHub. As a niche tool built in the Hoon programming language, it has a limited user base, meaning it has undergone minimal external security auditing or community testing compared to mainstream projects.

Verdict
Use with caution: The tool is actively maintained, but its low community visibility, plain-text authentication setup, and flagged build script commands warrant a thorough manual code review before deploying it on a sensitive or main Urbit ship.
SUMMARY

A general-purpose MCP interface for Urbit, a networked personal server.

README.md

Urbit MCP

A general-purpose Model Context Protocol interface for Urbit.

Developer Setup

1. Build and Install

  • Requires a running Urbit ship, real or fake, running on a machine you have terminal access to.
  • Requires peru package manager. Install and set that up if you don't have it already. Make sure peru --version works.

Create and mount the desk on your Urbit ship:

> |new-desk %mcp
> |mount %mcp

In the urbit-mcp folder, run the build script. By default this will install dependencies into /dist in this folder. Use the -p argument to additionally copy the %mcp source and its dependencies into your ship's desk. This script will take a minute if it's your first time running it.

$ cd urbit-mcp
$ build.sh -p ~/path/to/zod/mcp

> |commit %mcp
> |install our %mcp

2. Authentication Setup

Get your ship's web login code from the Dojo:

> +code
lidlut-tabwed-pillex-ridrup
~zod:dojo>

Authenticate and get session cookie:

curl -i http://localhost:80/~/login -X POST -d "password=lidlut-tabwed-pillex-ridrup"

Extract the cookie from the set-cookie header, which will look like this:

urbauth-~your-ship=0v3.j2062.1prp1.qne4e.goq3h.ksudm

3A. Register with Claude

Add the MCP server to Claude using HTTP transport:

claude mcp add --transport http zod http://localhost:80/mcp --header "Cookie: urbauth-~your-ship=0v3.j2062.1prp1.qne4e.goq3h.ksudm" --scope user

3B. Register with Codex

Codex requires the mcp-proxy python package to function. Install with uvx mcp-proxy, then append this to your ~/.codex/config.toml:

[mcp_servers.fen]
command = "uvx"
args = [
  "mcp-proxy",
  "--transport", "streamablehttp",
  "--headers", "Cookie", "urbauth-~your-ship=0v2.20fhu.t7ki1.cftjr.3s8bv.d9i5l",
  "http://localhost:80/mcp"
]

Usage

Tools

Just ask! You can see the default tools here.

You can ask your LLM to add new Tools. Give it a description (and ideally, examples) and it will do its best, or provide a Hoon thread for it to adapt to run in %mcp-server. Threads in %mcp-server must be of signature $-((map @t argument:tool:mcp) shed:khan).

Prompts (slash commands)

MCP prompts for most default tools are available as slash commands, using the format /mcp__<mcp server>__<tool name>.

/mcp__zod__commit-desk mcp

Running these will append a predefined prompt to the conversation and call out to the LLM provider.

Type / in Claude Code to see available Prompts.

You can ask your LLM to add new Prompts. These can be any reusable snippet of text you like.

Resources (@ mentions)

MCP resources can be referenced with an @ mention to pull the contents into the context window.

@zod:https://docs.urbit.org/llms.txt

Type @ in Claude Code to see available Resources.

You can ask your LLM to add new Resources by providing an https:// URI to a public webpage or a beam:// URI to a file in Clay.

Contributing

This repo requires commits to be signed with a Groundwire identity. PRs with unsigned commits will be rejected by CI.

Setup commit signing

You need an Urbit ship running the %vitriol agent.

Quick install:

./hooks/install.sh <your-ship-url>/vitriol "<auth-cookie>"

Manual install:

git config gpg.program /path/to/hooks/groundwire-sign
git config commit.gpgsign true
git config groundwire.sign-endpoint <your-ship-url>/vitriol
git config groundwire.sign-token "<auth-cookie>"

Once configured, all commits will be automatically signed with your ship's Ed25519 networking key. The CI verifies signatures against on-chain keys via vitriol.bot.

Re-signing existing commits

If you have unsigned commits on a branch:

git rebase --exec "true" HEAD~N

(where N is the number of commits to re-sign)

Development

Build Commands

  • ./build.sh - Build full desk
  • ./build.sh build-dev - Build dependencies
  • ./build.sh clean - Clean build directories
  • ./build.sh -p /path/to/desk - Build and copy to a ship's desk

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