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Cairn
Free & open source

Think clearly.
Ship faster.

Cairn is a local-first project management app with AI built in. No account. No cloud. No subscription.

Download for free View docs
Cairn app screenshot

Yours, completely

Everything lives in plain markdown files on your machine. No cloud, no account, no lock-in.

AI that works offline

Chat with your project, generate PRDs, spawn tasks — all through your own AI endpoint.

Fast by design

SQLite-backed, Electron-native. Opens instantly. Works without internet.

Notes

Markdown that actually belongs to you

A full markdown editor with live preview. Every note is a plain .md file with YAML frontmatter — readable and editable in any text editor, forever.

  • Split-pane live preview
  • Syntax highlighting for 100+ languages in code blocks
  • Mermaid diagrams render inline — flowcharts, sequence diagrams, ER diagrams
  • Table of contents auto-generated from headings
  • AI text actions: rephrase, summarize, expand, fix grammar
  • External edits sync back automatically
Notes editor
Kanban

A board that stays out of your way

Drag-and-drop task cards across configurable columns. Priority, due dates, and note links — without the ceremony.

  • Default columns: Backlog, Todo, In Progress, Review, Done
  • Priority levels: low / medium / high / urgent
  • Due dates and card-to-note linking
  • AI can create and move cards via chat
Kanban board
AI Chat

An AI that can actually do things

Chat with your project in a persistent side panel. The AI reads notes, creates tasks, moves cards, and writes PRDs — live, with a tool call activity feed so you see exactly what it's doing.

  • OpenAI, Ollama, LM Studio — any compatible endpoint
  • No API key needed for local endpoints
  • Live tool call activity feed
  • Streaming responses — word-by-word, live cursor
  • Chat thread history — browse and resume past conversations
AI Chat
PRD Generator

From idea to structured spec in seconds

Describe a feature in plain language. Cairn generates a full PRD with user stories, acceptance criteria, and open questions — then spawns the tasks directly onto your board.

  • Full PRD: overview, goals, user stories, requirements, acceptance criteria
  • Saved as an editable note
  • One-click task spawning
  • Bidirectional links: tasks know their PRD, PRDs know their tasks
PRD Generator
Dashboards

Live dashboards, built by AI

Ask the AI to generate an interactive HTML dashboard for any project. Dashboards fetch live data on every load and update automatically — no rebuild, no deploy.

  • Template gallery: Project Health, Daily Standup, Priority Board, Workspace Overview
  • Edit the HTML directly with a built-in code editor
  • Runtime errors surface a "Fix with AI" button
  • Fully sandboxed — no network access, no external URLs
  • Theme-aware — dashboards inherit your light/dark preference automatically
Dashboards
Idea Flow

A canvas for thinking before you build

Drag nodes onto a freeform canvas, connect them with edges, and let the AI summarise any subgraph. Idea Flow bridges the gap between raw thinking and structured project work — without leaving Cairn.

  • Idea, URL, note reference, and task reference node types
  • Group nodes — colour-coded containers; drag nodes in or out to nest and release
  • Auto-layout with a single click — left-to-right or top-to-bottom
  • AI Summary node generates summaries from any connected subgraph
  • Promote an idea directly to a board task — edges re-wired automatically
  • URL nodes fetch Open Graph metadata with one click
  • Drag a note or task from the sidebar to create a reference node instantly
  • Full MCP/AI access — build and connect nodes from the AI chat or any MCP client
Idea Flow canvas
Knowledge Graph

Everything you know, connected

A workspace-level view of every relationship between your notes, tasks, projects, and tags. Switch between a force-directed graph and a radial hierarchy tree, with auto-discovered co-mentions, keyword similarity, and shared assignees.

  • Force graph — physics-based layout; clusters related content naturally
  • Radial tree — hierarchy view rooted at the workspace, with cross-project chord overlays
  • Click any node to open a detail panel and navigate to the source
  • Filter by project, node type, or relationship type
  • Auto-discovers relationships: co-mentions, keyword similarity, shared assignees
  • Full MCP access — get_knowledge_graph and get_neighbors for AI research traversal
Knowledge Graph
Insights

Seven ways to see your work

A dedicated analytics view that surfaces patterns across every project. A ridgeline of task activity, a beeswarm of due dates, a bullet chart of project health, a Sankey of task flow through your pipeline — and three more. All scoped to whatever projects you care about.

  • Ridgeline — task activity as a joy plot, one row per project
  • Beeswarm — tasks on a shared time axis; dot size encodes priority
  • Bullet — completion bars with urgency bands and overdue markers
  • Sankey — task flow from Backlog to Done; click a stage to inspect
  • Timeline — all tasks with due dates sorted chronologically
  • Matrix — tag co-occurrence heatmap; hover to preview, click to pin
  • Table — flat sortable list across all notes, tasks, and projects
Insights view
MCP Server

Your project, reachable from any AI client

Cairn ships a bundled MCP server. Connect Claude Desktop, OpenCode, Cursor — or any MCP-compatible client — and give your AI direct read/write access to your notes and tasks.

Writes appear in the Cairn UI instantly. No restart, no sync delay. Tools include patch_note for surgical edits — the AI replaces exactly what changed, without re-sending the whole document.

Read the MCP docs 
// .opencode/config.json
{
  "mcp": {
    "cairn": {
      "type": "local",
      "command": [
        "/Applications/Cairn.app/Contents/Resources/app.asar.unpacked/dist-mcp/cairn-mcp"
      ],
      "enabled": true
    }
  }
}

Undo works everywhere

Full undo/redo across notes, board, and Idea Flow. The command pattern coalesces rapid typing into a single undo step, and skips text inputs that handle it natively.

  • Cmd Z / Cmd Shift Z across notes, board tasks, and Idea Flow
  • 2 s coalescing for note edits — rapid typing is one undo step
  • History cleared on AI/MCP writes — use chat to revert AI changes

How Cairn compares

Cairn Notion Linear Obsidian
Local-first ✓ ✗ ✗ ✓
Plain markdown files ✓ ✗ ✗ ✓
Kanban board ✓ ✓ ✓ ✗
AI chat built in ✓ ✓ ✗ ✗
MCP server ✓ ✗ ✗ ✗
No account required ✓ ✗ ✗ ✓
Free ✓ Freemium Freemium ✓
Knowledge graph ✓ ✗ ✗ Partial

Frequently asked

Yes. Cairn is free and open source.

In a folder you choose on your own machine. A SQLite database and plain markdown files — nothing leaves your computer unless you put the folder in a cloud-synced location yourself.

Completely. The app, the board, the notes, and the AI chat (with a local endpoint like Ollama) all work without internet.

Any OpenAI-compatible endpoint. That includes OpenAI GPT models, Anthropic Claude (via compatible proxies), Ollama (local), and LM Studio (local).

Model Context Protocol is an open standard for giving AI assistants access to external tools. Cairn ships a bundled MCP server so tools like Claude Desktop, OpenCode, or Cursor can read and write your notes and tasks directly.

macOS, Windows, and Linux. Built with Electron.