JetBrains InnovationHub Apache-2.0 open source

The agentic IDE that gets better every time you use it.

Open a repo as a project. Cut isolated git-worktree workspaces. Pair with a real agent across Monaco tabs, terminals, and diffs — while your project's intent lives in a spec graph the agent actually reads.

ThinkRail runs on macOS, Windows, and Linux.

Install the local launcher; run thinkrail to open the browser UI.

Install the local launcher; run thinkrail to open the browser UI.

Install the local launcher; run thinkrail to open the browser UI.

Every workspace is a real git worktree — its own branch, its own cwd. Run several agents in parallel; each one's mess stays on its branch, and main stays clean until you say otherwise.

ThinkRail is built spec-first, and so are your projects: a connected graph of spec files lives beside the code, and the agent reads, searches, and maintains it with dedicated tools. Intent survives the session.

The pi coding agent runs in-process and owns models, skills, compaction, and cost. ThinkRail owns the workspace, the editor, and the wire — it never assembles prompts behind your back.

A project is any local git repo. A workspace is a git worktree cut from it — created in one click, listed in the rail, disposable without ceremony.

one repo, three parallel lines of thought

~/code/my-repo ← project └─ ~/.thinkrail/worktrees/ ├─ workspace-1 ⎇ feature/auth agent A building ├─ workspace-2 ⎇ fix/flaky-test agent B fixing └─ workspace-3 ⎇ spike/ideas you, exploring

Own branch + cwd per workspace — files, diffs, terminals, and chats all scope to it.

Switch workspaces instantly; nothing reloads, nothing leaks across.

Merge the good one, delete the rest. Your repo never noticed the chaos.

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Watch the agent work — or work beside it — without leaving the page.

The VS Code editor engine: syntax everywhere, rendered markdown with a source toggle, file tabs per workspace.

The active worktree at a glance — like the rail on the right of this very page.

A live git diff of the workspace branch, so you review the agent's work as it lands.

Real PTYs scoped to the worktree — run the tests yourself while the agent keeps typing.

This transcript is a real pi session, captured in ThinkRail while it worked on its own repo:

ThinkRail is the agentic IDE built around the pi coding agent — a thin host that runs pi in-process and bridges it to a rich UI, while pi owns models, skills, compaction, cost, and session state.

Every module carries a SPEC.md with frontmatter linking it into a graph — goal, architecture, modules, tasks. The bundled pi-spec-graph extension gives the agent spec_* tools to search, navigate, and maintain it, and the Specs tab renders the live graph of your worktree:

---

id: module-server type: module-design status: active parent: architecture

Plain markdown, plain frontmatter, versioned with the code — reading the specs is enough to understand an area and formulate the next task. The agent keeps them honest as it builds.

Linux: extract the archive, run ./installer, and check the native library requirements.

Install the local launcher, then run thinkrail to open the browser UI.

Requires git and an authenticated pi provider. See all releases and advanced CLI options.

ThinkRail is a JetBrains InnovationHub project, licensed Apache-2.0. The repo is developed spec-first — the top-level specs are the product's ground truth, and this website is itself a module with a SPEC.md.