Give every task
its own ground.

Cairn FoundryTM is a desktop workspace for developing with AI coding agents. Editor, terminals, git and your coding CLI in one window, and each piece of work isolated in its own instance, so several tasks move at once without stepping on each other.

Download for free Read the source

AGPL-3.0 / macOS, Linux, Windows / no account, no telemetry

the name

A cairn does not walk for you.
It keeps you on the trail.

Agents write most of the code now. The bottleneck moved: it is no longer typing, it is staying oriented, across five branches, three conversations and a test suite that just went red.

Cairn Foundry is built for that job. It does not try to be a smarter agent; it is the marker on the trail. It holds separate ground for each task, keeps every conversation, terminal and diff exactly where you left it, and lets you look away without losing the path.

the ground rule

One task,
one instance.

An agent that edits files needs its own files to edit. Cairn Foundry never lets two tasks share a checkout: each one works on real, separate ground, and your main branch never notices any of it.

Project

A git repository, registered once.

Instance

One unit of work inside a project: an isolated checkout on its own branch, with its own editor tabs, terminals and agent conversations.

Switching

Swaps the whole state at once. The other instance keeps running: its agent keeps answering, its tests keep going, its terminal keeps scrolling.

checkout-service
main never touched
  • feat/tickets-page
    agent running
  • fix/pty-resize
    tests green
  • chore/deps
    in review

Three instances of one project. Zero collisions.

the workspace

Six steps. One window.

A task walks through the same stations every time: read, delegate, review, verify, commit, ship. Cairn Foundry makes each one a step of the workspace instead of a window on another screen.

cairn - checkout-service / feat/tickets-page
src/
routes/
tickets.ts
board.svelte
lib/
api.ts
export function planBacklog(tickets: Ticket[]) {
  const ordered = rank(tickets)
  return ordered.map(toInstance)
}
// go to definition: rank() - lib/api.ts:41

A CodeMirror 6 editor with language servers, diagnostics, go to definition, a minimap, diff view, and Markdown that renders inline while staying editable.

the agent

Your CLI, not ours.

Cairn Foundry does not wrap your coding agent behind its own chat. It launches the CLI itself, as it is, in an embedded terminal: its own account, its own models, its own permissions, its own slash commands, its own updates. Nothing reinterpreted.

What Cairn Foundry adds is the part a terminal forgets: the list of conversations per instance and per project, and the ability to reopen any of them exactly where it stopped. Skills, MCP servers and subagents are managed from one hub, written into each CLI's own format.

  • $ claude Claude Code
  • $ codex Codex
  • $ gemini Gemini CLI
  • $ opencode OpenCode
  • $ copilot GitHub Copilot
  • $ cursor-agent Cursor CLI
  • $ amp Amp
  • $ goose Goose
  • $ qwen Qwen Code
  • $ droid Factory Droid
  • $ antigravity Antigravity
  • $ vibe Vibe

No API keys to paste. No accounts on top of your accounts. And a single switch in Settings turns every AI feature off, entirely.

local-first

The trail is yours.

Everything comes back

Close Cairn Foundry mid-thought. It reopens on the same step, the same tabs, the same cursor and scroll position, the same terminals, the same conversations. A restart costs nothing.

Everything stays here

All application data lives in ~/.cairn on your disk: settings, projects, instances, editor state, conversations. No account, no telemetry, no server of ours in the loop.

Everything works offline

The editor, git, terminals, search and tests run without a connection. Only your agent needs the network, and that traffic goes through your CLI, on your terms.

~/.cairn/projects/checkout-service/instances/feat-tickets-page

the build

Built like a tool,
not a platform.

Cairn Foundry is written from scratch: a Rust core in a Tauri shell, a Svelte interface, a CodeMirror editor, real PTYs. No Electron, no fork of someone else's editor, no marketplace to weigh it down. Every line is in the open, under a license that keeps it that way.

Browse the repository
Core
Rust
Shell
Tauri v2, no Electron
Interface
Svelte 5
Editor
CodeMirror 6 + LSP
Terminals
Real PTYs
Integrations
GitLab, GitHub, Jira
Languages
English + French
License
AGPL-3.0, free forever

the trail so far

One stone at a time.

Cairn Foundry ships every few days, and every user-visible change is written down. This is the path from the first complete workspace to 1.0.

  1. v1.0.0 2026-08-31

    The first public release

    A workspace where each task gets its own instance, with the editor, the git view, the tests, the review, the pipelines and your coding CLI side by side.

  2. v0.19.0 2026-08-31

    Your CLI, launched as it is

    The Agent step stops wrapping your coding CLI and runs it: Claude Code, Codex, Gemini CLI, OpenCode, Copilot and a dozen others, opened as they are in an embedded terminal and reopened later where they left off.

  3. v0.18.0 2026-08-30

    Review as a guided reading

    The AI writes the tour of the branch, chapter by chapter, and your comments go up to GitLab or GitHub.

  4. v0.17.0 2026-08-29

    Integrations

    GitLab, GitHub and Jira come into Cairn Foundry: tickets, merge requests, pipelines and reviews, without leaving the workspace.

  5. v0.16.0 2026-08-17

    Tests, for real

    The Tests step runs your suite, streams results as they arrive, and puts the failing line one click away.

  6. v0.14.0 2026-08-15

    Agents in conversation

    Five coding agents hold a conversation, and the skills, subagents and MCP servers they read are managed from Cairn Foundry.

  7. v0.13.0 2026-08-08

    The editor learns your languages

    Language servers, diagnostics, go to definition, and native formatting.

  8. v0.12.0 2026-08-02

    Navigation and search

    Everywhere, and faster.

  9. v0.10.0 2026-07-13

    The first complete workspace

    Editor, git and agent side by side.

Set your first stone.

Free, open source, yours. Bring the coding CLI you already pay for; Cairn Foundry adds nothing on top.

Download Cairn Foundry Star on GitHub
  • macOS Apple Silicon and Intel
  • Linux AppImage and deb
  • Windows x64 installer