ThinkRail from JetBrains

JetBrains released ThinkRail, an Apache-2.0 open-source agentic IDE that runs the pi coding agent in-process and gives each agent session its own git worktree workspace with a separate branch and working directory. ThinkRail runs on macOS, Windows, and Linux, installs via a command-line launcher that opens a browser UI, and pairs the Monaco editor engine with per-workspace file trees, live git diffs, and real PTY terminals, while a spec graph of files beside the code serves as the intent the agent reads and maintains. The release matters because it isolates parallel agents' changes on disposable branches so the main branch stays clean until the user merges.

< -- README.md -- JetBrains InnovationHub Apache-2.0 open source ThinkRail 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. macOS 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 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 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 https://pi.dev 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: 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 : 1. Engine host packages/server — createServer runs an HTTP+WS host plus an AgentSessionManager : one in-process pi session per tab. 2. The wire packages/contracts — the typed, versioned protocol between host and UI. Types only. 3. UI client apps/web — mobile-first React that ships independently and dials any host over the wire. - 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: main spec arch module submodule 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 https://github.com/JetBrains/thinkrail install . Browser UI via command line Install the local launcher, then run thinkrail to open the browser UI. curl -fsSL https://raw.githubusercontent.com/JetBrains/thinkrail/main/install.sh | bash irm https://raw.githubusercontent.com/JetBrains/thinkrail/main/install.ps1 | iex powershell -c "irm https://raw.githubusercontent.com/JetBrains/thinkrail/main/install.ps1 | iex" Requires git and an authenticated pi provider. See all releases https://github.com/JetBrains/thinkrail/releases and advanced CLI options https://github.com/JetBrains/thinkrail install .