Pi-mono: Claude Code Alternative AI Coding Agent 5.9k Stars

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pi-mono: Build an AI Coding Agent Directly in Your Terminal

  • GitHub Stars: 5.9k
  • Language: TypeScript 96.5%
  • License: MIT

Why This Project is Trending

A developer felt that Claude Code had become too complex. Mario Zechner experimented with LLM coding tools for three years before finally deciding to build his own.[Mario Zechner]

pi-mono is an AI agent toolkit born from the philosophy of “don’t build it if you don’t need it.” It starts with a 1000-token system prompt and four core tools (read, write, edit, bash). Compared to Claude Code’s thousands of tokens worth of prompts, it’s extremely lightweight.[GitHub]

What Can You Do?

  • Integrated LLM API: Use over 15 providers, including OpenAI, Anthropic, Google, Azure, Mistral, and Groq, with a single interface.
  • Coding Agent CLI: Write, test, and debug code interactively in the terminal.
  • Session Management: Interrupt and resume tasks, and even branch like with Git.
  • Slack Bot: Delegate Slack messages to the coding agent.
  • vLLM Pod Management: Deploy and manage your own models on GPU pods.
  • TUI/Web UI Library: Create your own AI chat interface.

Quick Start

# Installation
npm install @mariozechner/pi-coding-agent

# Execution
npx pi

# Or build from source
git clone https://github.com/badlogic/pi-mono
cd pi-mono
npm install && npm run build
./pi-test.sh

Where Would It Be Useful?

If you find Claude Code’s monthly fee of ₩200,000 burdensome and you’re a developer who primarily works in the terminal, pi could be an alternative. You only pay for the API costs.

If you want to use a self-hosted LLM but existing tools don’t support it well, pi is the answer. It even has a built-in vLLM pod management feature.

Personally, I think “transparency” is the biggest advantage. Claude Code has sub-agents running internally that you can’t see what they’re doing. With pi, you can directly check all model interactions.

Things to Note

  • Minimalism is the philosophy. MCP (Model Context Protocol) support is intentionally omitted.
  • Full access permissions, which they call “YOLO mode,” are the default. Be careful because permission checks are looser than Claude Code.
  • Documentation is still lacking. You need to read the AGENTS.md file carefully.

Similar Projects

Aider: Also an open-source terminal coding tool. It’s similar in that it’s model-agnostic, but pi covers a wider range (UI library, pod management, etc.).[AIMultiple]

Claude Code: Has more features, but requires a monthly subscription and has limited customization. pi allows you to freely add features with TypeScript extensions.[Northflank]

Cursor: An IDE with integrated AI. If you prefer a GUI over a terminal, Cursor is better.

Frequently Asked Questions (FAQ)

Q: Is it free to use?

A: pi itself is completely free under the MIT license. However, if you use external LLM APIs such as OpenAI or Anthropic, you will incur those costs. If you use Ollama or self-hosted vLLM locally, you can use it without API costs.

Q: Is the performance good enough to replace Claude Code?

A: In the Terminal-Bench 2.0 benchmark, pi with Claude Opus 4.5 attached showed results comparable to Codex, Cursor, and Windsurf. This proves that a minimalist approach doesn’t compromise performance.

Q: Is Korean supported?

A: The UI is in English, but if the LLM you connect to supports Korean, you can code while conversing in Korean. If you connect to Claude or GPT-4, you can write code with Korean prompts.

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References

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