ThinkRail

JetBrains' open-source agentic IDE built around the pi coding agent — every task runs in its own isolated git-worktree workspace with a spec graph the agent actually reads, so parallel agents never wreck your main checkout

Open Source Coding & Development
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What is ThinkRail?

ThinkRail is JetBrains' open-source agentic IDE built around the pi coding agent. It is a thin host that runs pi in-process — pi owns models, skills, compaction and cost — while ThinkRail owns the workspace, the editor and the wire, and never assembles prompts behind your back.

Every task runs in its own isolated git-worktree workspace with its own branch, and project intent lives in a spec graph of SPEC.md files that the agent reads, searches and maintains with dedicated tools — so parallel agents never wreck your main checkout, and intent survives the session.

Key features

  • Isolated git-worktree workspaces — one branch and working directory per task, created in one click and disposable without ceremony
  • Spec graph the agent actually reads — SPEC.md files with frontmatter, searched and maintained with spec_* tools via the pi-spec-graph extension
  • Real IDE around the agent — Monaco editor tabs, files tree, live git diff and real PTY terminals scoped to the worktree
  • pi coding agent in-process — pi owns models, skills, compaction and cost; pick the model per session with live token and cost tracking
  • Streaming chats — several sessions per workspace running concurrently, steer a running turn or queue a follow-up
  • Installers for macOS (Apple Silicon), Windows x64 and Linux (Ubuntu 24.04+), plus a browser UI via the command line

Pros

  • Apache-2.0 open source from JetBrains
  • Parallel agents stay on their own branches — main stays clean until you merge
  • Intent survives the session through the spec graph
  • No prompt assembly behind your back — the host never hides what the agent is told

Cons

  • Requires git and an authenticated pi provider — it does not work without them
  • Install page lists macOS Apple Silicon only and Linux as Ubuntu 24.04+

ThinkRail at a glance

PricingOpen Source
CategoryCoding & Development
Platformsmac, windows, linux
CompanyJetBrains
Best forDevelopers running parallel coding agents who want worktree isolation and a spec graph the agent actually reads
Official websitethinkrail.ai
agentic IDEcoding agentpigit worktreesspec graphJetBrains

How to choose the right Coding & Development tool

The right coding tool depends on where you write code and how much of your codebase it can understand. IDE integration is the first filter — a tool that lives in your editor, sees your project files and respects your stack will help far more than a general chatbot you paste snippets into. Look for accurate completions, clear explanations of suggested changes, and strong refactoring and debugging support for your main languages. Privacy deserves real attention: check whether your code is used for training, and whether a self-hosted or enterprise option exists for sensitive projects. Price against the hours it actually saves — most developers feel the difference within the first week of real use.

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ThinkRail FAQs

What is ThinkRail?

ThinkRail is JetBrains' open-source agentic IDE built around the pi coding agent. It is a thin host that runs pi in-process — pi owns models, skills, compaction and cost — while ThinkRail owns the workspace, the editor and the wire, and never assembles prompts behind your back.

What are the main features of ThinkRail?

ThinkRail offers Isolated git-worktree workspaces — one branch and working directory per task, created in one click and disposable without ceremony, Spec graph the agent actually reads — SPEC.md files with frontmatter, searched and maintained with spec_* tools via the pi-spec-graph extension, Real IDE around the agent — Monaco editor tabs, files tree, live git diff and real PTY terminals scoped to the worktree, pi coding agent in-process — pi owns models, skills, compaction and cost; pick the model per session with live token and cost tracking, Streaming chats — several sessions per workspace running concurrently, steer a running turn or queue a follow-up and Installers for macOS (Apple Silicon), Windows x64 and Linux (Ubuntu 24.04+), plus a browser UI via the command line.

How much does ThinkRail cost?

ThinkRail is open source, so the software itself is free to download, use and self-host. Your only costs are the infrastructure you run it on and any paid services you connect to it.

What are the pros and cons of ThinkRail?

Strengths of ThinkRail include Apache-2.0 open source from JetBrains; Parallel agents stay on their own branches — main stays clean until you merge; Intent survives the session through the spec graph. On the downside, Requires git and an authenticated pi provider — it does not work without them; Install page lists macOS Apple Silicon only and Linux as Ubuntu 24.04+.