ThinkRail — the agentic IDE that gets better every time you use it

<!-- README.md --> 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. macOS Apple Silicon Browser UI via command line Install the local launcher; run thinkrail to open the browser UI. curl -fsSL https://raw.githubusercontent.com/JetBrains/thinkrail/main/install.sh | bash Windows Windows x64 Browser UI via command line Install the local launcher; run thinkrail to open the browser UI. PowerShell irm https://raw.githubusercontent.com/JetBrains/thinkrail/main/install.ps1 | iex Command Prompt (cmd) powershell -c "irm https://raw.githubusercontent.com/JetBrains/thinkrail/main/install.ps1 | iex" WSL curl -fsSL https://raw.githubusercontent.com/JetBrains/thinkrail/main/install.sh | bash Linux Ubuntu 24.04+ Browser UI via command line Install the local launcher; run thinkrail to open the browser UI.

curl -fsSL https://raw.githubusercontent.com/JetBrains/thinkrail/main/install.sh | bash <!-- WHY ThinkRail --> Why ThinkRail Agents deserve worktrees, not your working tree.

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.

Specs are the ground truth.

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.

A thin host, a real engine. 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. <!-- FEATURES / worktrees --> Projects → workspaces 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. <!-- FEATURES / editor --> A real IDE around the agent Watch the agent work — or work beside it — without leaving the page. Monaco editor tabs The VS Code editor engine: syntax everywhere, rendered markdown with a source toggle, file tabs per workspace. Files tree The active worktree at a glance — like the rail on the right of this very page. Changes A live git diff of the workspace branch, so you review the agent's work as it lands. Terminals Real PTYs scoped to the worktree — run the tests yourself while the agent keeps typing. <!-- FEATURES / agent-chat --> Chats that stream like the engine thinks This transcript is a real pi session, captured in ThinkRail while it worked on its own repo: Quick tour: what is ThinkRail, and what are the three rings of its architecture?

Keep it brief.

read goal-and-requirements.md · architecture.md 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. The three rings: Engine host (packages/server) — createServer() runs an HTTP+WS host plus an AgentSessionManager: one in-process pi session per tab. The wire (packages/contracts) — the typed, versioned protocol between host and UI.

Types only.

UI client (apps/web) — mobile-first React that ships independently and dials any host over the wire. Done 5s · 25.9k tok · $0.17 Several sessions per workspace, streaming concurrently. Pick the model per session; tokens and cost tick live in the header. Steer a running turn or queue a follow-up — no waiting for the agent to finish. Interactive tools: the agent can ask structured questions back, right in the chat. <!-- FEATURES / specs --> Specs are first-class 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: ThinkRail — product goal and scope main spec ThinkRail — top-level architecture arch Engine host (server library) module agent — in-process pi sessions submodule Web UI client module --- 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. <!-- INSTALL.md --> Install Choose your platform and start working. macOS Apple Silicon Windows Windows x64 Linux Ubuntu 24.04+ Linux: extract the archive, run ./installer, and check the native library requirements.

Browser UI via command line Install the local launcher, then run thinkrail to open the browser UI.

See all releases and advanced CLI options.

<!-- CONTRIBUTING --> Open source, spec-first 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.

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