Cairn

Name: Cairn
Author: cybort360

by cybort360version 0.1.2i★ –iRuns on your computer

Registry nameio.github.cybort360/cairn-mcp

Install

Overview

Description from the maker (original English)

Log Claude Code work sessions, file edits, and tasks to your Cairn account.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Developer tools
You need to fill in: CAIRN_TOKEN

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: CAIRN_TOKEN, CAIRN_API_URL

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

PyPIPython’s uv installed (for the uvx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "cairn": {
      "command": "uvx",
      "args": [
        "cairn-mcp"
      ],
      "env": {
        "CAIRN_TOKEN": "your-value",
        "CAIRN_API_URL": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add cairn --env CAIRN_TOKEN=your-value --env CAIRN_API_URL=your-value -- uvx cairn-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "cairn": {
      "command": "uvx",
      "args": [
        "cairn-mcp"
      ],
      "env": {
        "CAIRN_TOKEN": "your-value",
        "CAIRN_API_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "cairn": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "cairn-mcp"
      ],
      "env": {
        "CAIRN_TOKEN": "your-value",
        "CAIRN_API_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

CAIRN_TOKEN secret env
Your Cairn API token, copied from the web app account menu. If unset, the server reads it from ~/.cairn_token.
CAIRN_API_URL env
Base URL of the Cairn API. Defaults to production.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 8, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account cybort360, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Developer toolsi

More stars than 0% of the other 4923 servers in this category
Published to the registry more recently than 21% of the other 4923 servers in this category
Basic checks equal to or better than 100% of the other 4923 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Cairn safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: CAIRN_TOKEN

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.2) reached the registry 5 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Python (uv) on your computer.

What can I use instead?

In the same category: GitHub, Desktop Commander, Cloudflare MCP

Alternatives

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Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Cairn

A work tracker that remembers what you did. It captures your coding sessions, the files you touch, tasks moving from pending to done, and project notes, then keeps them in one place with daily and weekly rollups. The name is the pile of stones that marks a trail.

Cairn runs as a multi-tenant web app on Vercel with a Neon Postgres database. Each account signs up, logs in, and only ever sees its own data.

How it's built

The whole server is the Python standard library plus one dependency (psycopg). No framework.

api/index.py — the Vercel serverless entrypoint. Vercel's Python runtime treats it as a catch-all, so every request lands here.
lib/handler.py — routing. The same BaseHTTPRequestHandler runs three ways: the Vercel function, the local dev server, and the tests.
lib/data.py — every SQL statement, each one scoped by user_id.
lib/db.py — Neon connection (pooled endpoint) plus small query helpers.
lib/auth.py — PBKDF2 password hashing, sessions, and token resolution.
lib/limits.py — signup/login rate limiting and per-account quota caps, both backed by Postgres.
lib/assets.py — the single-page app and favicon, embedded as base64 so they ship inside the function bundle. Generated by build_assets.py; re-run it after editing static/.

Local development

You need a Postgres to point at. A throwaway one in Docker works:

docker run -d --name cairn_pg -e POSTGRES_PASSWORD=pw -e POSTGRES_DB=cairn -p 5432:5432 postgres:16-alpine

python3 -m venv .venv && .venv/bin/pip install 'psycopg[binary]' export DATABASE_URL="postgres://postgres:pw@127.0.0.1:5432/cairn" .venv/bin/python dev.py --init # create the schema, then serve on :8765

Tests run against that same database:

.venv/bin/python tests/smoke.py        # core CRUD + isolation

.venv/bin/python tests/test_limits.py # rate limiting + quotas .venv/bin/python tests/test_sp3.py # file activity + filtered lists

Deployment

Pushing to main deploys to production through the Vercel GitHub integration. DATABASE_URL and the other Neon variables come from the Vercel ↔ Neon integration; the app reads the pooled connection string. Schema changes go on with initdb.py against the direct (unpooled) URL.

The agent side

The agent/ folder is the MCP server and two Claude Code hooks that run on your machine. They talk to this API over HTTPS using your account's token, so anything Claude Code does flows into your Cairn account. The server gives Claude a set of cairn tools; the hooks log sessions and file edits on their own.

On Claude Code the quickest install is the plugin — this repo doubles as a plugin marketplace (.claude-plugin/marketplace.json):

/plugin marketplace add https://github.com/cybort360/cairn

/plugin install cairn@cairn

That wires up the MCP server and both hooks; you just save your token to ~/.cairn_token (it needs uv on your PATH). The manual route — clone, venv, claude mcp add — is in agent/README.md. The web app deploy ignores agent/; it's client-side only.

Design notes

Each sub-project that built Cairn has a spec under docs/superpowers/specs/: the cloud core, the auth hardening, and the local agent cutover. Read those if you want the reasoning behind a decision rather than just the code.

Cairn

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Developer toolsi

Common questions

Alternatives

GitHub

Desktop Commander

Cloudflare MCP

README from the maker

Cairn

How it's built

Local development

Deployment

The agent side

Design notes