It gives the assistant a configured command for starting Cairn. The input does not explain what Cairn itself can do.

cairn — MCP server for Claude Code by isaacriehm

cairn

cairn is an MCP server for Claude Code from isaacriehm/cairn. Its token cost is not measured, scanned A, original, MIT.

An MCP server configuration for Cairn, a tool that runs through Node.js. MCP is a standard way for an AI assistant to connect to external tools and services.

In plain words

What is it for?: Use it when an assistant needs to start the Cairn MCP service with the specified model-provider setting.
Why use it?: It gives the assistant a configured command for starting Cairn. The input does not explain what Cairn itself can do.

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable. Also seen: listed in a Claude config.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the cairn plugin — 5 skills, 4 commands, 5 agents, 5 hooks, 1 MCP server shipped together

Good fit Use it when an assistant needs to start the Cairn MCP service with the specified model-provider setting.

Compare 6 mcp servers from other repositories ↓

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code

/plugin marketplace add isaacriehm/cairn

Claude Code

/plugin install cairn

Made for: Claude Code.

Or install cairn, the plugin that ships this one along with the rest of its 5 skills, 4 commands, 5 agents, 5 hooks, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/mcp/isaacriehm/cairn/cairn-plugin-cairn.svg)](https://agentmods.dev/mcp/isaacriehm/cairn/cairn-plugin-cairn)

Your own site

<a href="https://agentmods.dev/mcp/isaacriehm/cairn/cairn-plugin-cairn"><img src="https://agentmods.dev/badge/mcp/isaacriehm/cairn/cairn-plugin-cairn.svg" alt="Measured on agentmods" height="20"></a>

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

cairn scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

packages/cairn-plugin/.mcp.json · 12 lines

What it actually says

{
  "cairn": {
    "command": "node",
    "args": [
      "${CLAUDE_PLUGIN_ROOT}/dist/cli.mjs",
      "mcp",
      "serve",
      "--model-provider",
      "claude"
    ]
  }
}

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

8d ago First seen · 12 lines scan A 817b4f9f71fc

Subscribe to this mod's changes

cairn is an MCP server published in the GitHub repository isaacriehm/cairn (6 stars, last pushed 1mo ago), licensed MIT. Its token cost is not measured: an MCP server costs its tool schemas, not its config file. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Claude Code adr ai-agents ai-memory anthropic claude

cairn

Getting it into your agent

Wrote this? Show the measurements

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

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