An AI coding agent that plans before it touches your files

What it does Plandex is a terminal-based AI coding agent that breaks large tasks into planned steps and executes them across dozens of files. It keeps all generated changes in a cumulative diff review sandbox until you approve them, and can run terminal commands, builds, tests, and even browser debugging autonomously. Written in Go, it targets real-world projects that have grown large enough to overwhelm simpler AI assistants.

The interesting bit Instead of treating your repo as a flat text dump, Plandex uses tree-sitter to generate project maps and manages up to a 2-million-token context window, loading only what each step needs. It also lets you mix and match models from Anthropic, OpenAI, Google, and open-source providers in curated packs, switching between full autonomy and fine-grained step-by-step control as the task demands.

Key highlights

• Sandboxed workflow: AI changes live in a review layer until explicitly applied, with rollback support.
• Large-project resilience: handles ~2M tokens of active context and indexes 20M+ token directories via tree-sitter maps for 30+ languages.
• Multi-model by design: curated model packs let you trade off speed, cost, and capability across providers.
• Built-in debugging: automatically debugs terminal commands (builds, tests, linters) and browser apps if Chrome is available.
• Plan-level version control: branch and compare different implementation paths or models before committing to code.
• Context caching across OpenAI, Anthropic, and Google models to reduce API costs and latency.
• Git integration with optional auto-commit and generated commit messages.

Caveats

• Plandex Cloud is winding down as of 10/3/2025 and no longer accepts new users; the project now expects you to self-host the server or run it locally.
• Windows support is limited to WSL; it does not run in CMD or PowerShell natively.
• Requires bringing your own API keys for model providers.

Verdict Developers managing large, messy codebases who want an AI assistant that plans before it writes—and keeps its experiments out of your repo—should try this. If you only need single-file autocomplete or a fully managed SaaS, look elsewhere.