Cairn

Name: Cairn
Author: luckyjackluo

by luckyjackluoversion 0.2.0i★ –iRuns on your computer

Registry nameio.github.luckyjackluo/cairn

Install

Overview

Description from the maker (original English)

Local-first file-organization tools for your AI agent: tag, query, and digest a folder. No cloud.

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: Other

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_WORKSPACE

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-server"
      ],
      "env": {
        "CAIRN_WORKSPACE": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add cairn --env CAIRN_WORKSPACE=your-value -- uvx cairn-mcp-server

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-server"
      ],
      "env": {
        "CAIRN_WORKSPACE": "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-server"
      ],
      "env": {
        "CAIRN_WORKSPACE": "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_WORKSPACE env
Path to the folder Cairn operates on. If unset, defaults to the current working directory. You can also pass --workspace on the command line instead.

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 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account luckyjackluo, 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 Otheri

More stars than 0% of the other 32727 servers in this category
Published to the registry more recently than 18% of the other 32727 servers in this category
Basic checks equal to or better than 100% of the other 32727 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?

The registry does not list a required key, though some servers ask you to sign in on first use.

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 (0.2.0) reached the registry 4 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: Spec Driven Development, Remote Desktop Commander, Foliosio

Alternatives

Servers in the same category from other makers, sorted by stars.

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

Spec Driven Development

by formulahendry

MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.

Runs on your computer★ 440MITUpdated 14 months ago

Install

Remote Desktop Commander

by desktop-commander

Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.

Runs in the cloud★ 211Updated 2 days ago

Install

Foliosio

by foliosio.com

Read your support inbox, tag conversations and save draft replies from your AI agent. Never sends.

Runs in the cloudUpdated today

Install

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 local-first, open-source harness for organizing your files with an AI agent.

Point Claude Code, Codex, Cursor — any MCP client — at a folder, and your agent gains a full file-organization toolset: list, read, search, grep, edit, move, tag, import documents, and semantically retrieve. No account, no cloud, no UI required. Your files never leave your machine.

claude mcp add cairn -- uvx cairn-mcp-server --workspace ~/Documents/notes

Then ask your agent to *"organize this folder and tag everything"* — it will, using tools that run locally over your own files.

A cairn is a stack of stones that marks a trail. This one keeps your files in

order and shows the way through them.

Quickstart (2 minutes)

If you use Claude Code, setup is one command — the only prerequisite is uv, which provides uvx:

# 1. Install uv if you don't have it (provides uvx)

curl -LsSf https://astral.sh/uv/install.sh | sh

2. Add Cairn to Claude Code, pointed at a folder you want organized

claude mcp add cairn -- uvx cairn-mcp-server --workspace ~/Documents/notes

Reopen Claude Code and ask:

*"Organize this folder and tag everything."*

Cairn's tools run locally over your files — reads happen freely, and any move/rename/edit asks for confirmation first. The first run auto-downloads the package (~5s); no clone, no build, no account.

[!TIP]

Point --workspace at a copy of some notes for your first run — Cairn can

move, rename, and edit files.

Using Codex? Same one-command flow (then run /mcp in a session to confirm):

codex mcp add cairn -- uvx cairn-mcp-server --workspace ~/Documents/notes

Using Cursor or another MCP client? Same package, JSON config:

{ "mcpServers": { "cairn": { "command": "uvx",

"args": ["cairn-mcp-server", "--workspace", "~/Documents/notes"] } } }

~ is expanded by Cairn, so ~/Documents/notes works in the CLI and in config files alike.

Just want to poke at it, no agent?

uvx cairn-cli --workspace ~/Documents/notes tree

Why a harness

The agent-harness ecosystem converged on a clear pattern: the model and the agent loop are commodities supplied by the client (Claude Code, Codex, OpenCode). The durable value is the tools and the local data. So Cairn ships *tools, not an agent* — the client provides the loop, the approval prompts (driven by our tool annotations), and the chat. Cairn is just the local file-organization toolset that snaps into whatever harness you already use.

Architecture

Everything is a thin adapter over one standard-library core, so the faces can never drift.

core/          cairn-core — the engine (stdlib only): the .uni document format,

file operations, tags, retrieval; optional document ingestion (docx/pdf/pptx/xlsx/md) and embeddings-based search. mcp-server/ cairn-mcp-server — MCP server: 26 tools with read-only/destructive annotations, resources, and prompts. ← the flagship cli/ cairn-cli — scriptable CLI, a local HTTP API (serve), and an mcp launcher. web/ cairn-web — optional zero-build local web UI (browse / edit / view / tag / search).

Use it

In Claude Code / Codex / Cursor (primary):

claude mcp add cairn -- uvx cairn-mcp-server --workspace ~/Documents/notes

with real-document import: uvx --with "cairn-core[convert]" cairn-mcp-server ...

The server exposes read-only tools (list, read, search, grep, retrieve) that the client runs freely, and destructive tools (move, delete, edit) that it confirms first — driven by MCP tool annotations, so you get approval prompts with no UI of ours.

As a CLI:

uvx cairn-cli --workspace ~/Documents/notes tree

uvx cairn-cli --workspace ~/Documents/notes retrieve "budget planning"

With the optional web UI:

pip install cairn-cli cairn-web

cairn --workspace ~/Documents/notes serve # → http://127.0.0.1:4177/

The `.uni` format

A .uni file is a small JSON document — { uuid, content: " ", metadata, tags } — with tags stored *in the file*. A workspace is just a directory: fully portable, no external database. Source documents (docx/pdf/pptx/…) import into editable .uni docs; the originals are kept by default.

Local-first & bring-your-own-key

No account, no login, no cloud sync. The filesystem is the source of truth.
The default retriever is lexical and needs nothing. Embeddings are opt-in and bring-your-own-key (any OpenAI-compatible endpoint, including local servers like Ollama or LM Studio); vectors live in a local SQLite index under /.cairn/ and never leave your machine.

Roadmap

Cairn is young. Rough direction, and where help is most welcome:

More document faces — richer frontmatter support (nested metadata, dates), and round-tripping edits back into imported source formats.
Smarter digests — summaries that use an embedding model when one is configured, and saved views (.cairn/views/*.md).
More retrieval backends — pluggable rerankers; first-class local-model presets (Ollama, LM Studio) beyond the generic OpenAI-compatible path.
Editor/agent integrations — thin recipes for wiring Cairn into common MCP clients and note-taking setups.
Packaging — signed releases and a Homebrew formula.

Have a use case that doesn't fit? Open an issue or start a discussion.

Contributing

Contributions of every size are welcome — see CONTRIBUTING.md for the project layout, dev setup, and how to add a tool. Good first issues are labeled good first issue.

Develop

make setup      # uv venv (3.11) + editable install of all packages + extras

make test # run the suite make serve WORKSPACE=~/Documents/notes # web UI

License

MIT — see LICENSE.

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 Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Foliosio

README from the maker

Cairn

Quickstart (2 minutes)

2. Add Cairn to Claude Code, pointed at a folder you want organized

Why a harness

Architecture

Use it

with real-document import: uvx --with "cairn-core[convert]" cairn-mcp-server ...

The .uni format

Local-first & bring-your-own-key

Roadmap

Contributing

Develop

License

The `.uni` format