Open-source AI coding agent (CLI)
Pi
Pi is Mario Zechner's MIT-licensed terminal coding agent, now maintained by Earendil. It ships a deliberately small core, with read, write, edit, and bash tools, and leaves the rest to TypeScript extensions: there is no built-in MCP, subagents, plan mode, or permission prompts. It connects to 15+ model providers and runs as an interactive TUI, in print or JSON mode, over RPC, or embedded through its SDK. It is the base that forks such as omp build on.
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Coding
Best for
- Developers who want to build their own agent workflow
- Switching between model providers without changing tools
- Embedding a coding agent in scripts or other programs
Not best for
- Developers who want MCP, subagents, or plan mode out of the box
- Teams that want permission prompts before each command
- Users who do not want to write or install extensions
Quick facts
- Vendor
- Earendil
- Category
- Open-source AI coding agent (CLI)
- Platforms
- Terminal, macOS, Linux, Windows
- Integrations
- Anthropic, OpenAI, Google, Amazon Bedrock, Mistral, Groq, npm
- Pricing
- Free and open source under the MIT license, with no hosted backend. You pay your model provider for usage.
In Depth: Pi
Key features
- Small core: read, write, edit, and bash tools
- TypeScript extensions, skills, prompt templates, themes, and packages
- 15+ providers, including Anthropic, OpenAI, Google, Bedrock, Mistral, and Groq
- Interactive TUI, print/JSON mode, RPC, and an SDK
- Session management
Pricing and access
Free and open source under the MIT license, with no hosted backend. You pay your model provider for usage.
Plans and limits change often. Confirm current pricing on pi.dev before you commit.
