| name | pi-mono-0-66-1 |
| description | Complete implementation guide for pi-mono monorepo architecture covering provider abstraction, agent runtime, terminal UI rendering, extension system, session management, and tool implementation patterns. Use when building, debugging, or extending the pi coding agent — a minimal terminal-based AI coding harness that runs in interactive, print, JSON, RPC, and SDK embedding modes. |
| license | MIT |
| author | Tangled <noreply@tangledgroup.com> |
| version | 0.1.0 |
| tags | ["ai-coding-agent","terminal-harness","extensions","tui","session-management","providers","tools"] |
| category | ai-tooling |
| external_references | ["https://github.com/badlogic/pi-mono","https://pi.dev/","https://www.npmjs.com/package/@mariozechner/pi-coding-agent"] |
pi-mono 0.66.1
Overview
Pi is a minimal terminal coding harness — an AI coding agent that runs in your terminal with four modes: interactive TUI, print (non-interactive), JSON event stream, and RPC for process integration. It also provides an SDK for embedding in other applications. Pi ships with powerful defaults but skips features like sub-agents and plan mode by design, instead letting you build what you want via TypeScript extensions, skills, prompt templates, and themes.
The monorepo (pi-mono) contains four core packages:
@mariozechner/pi-ai — LLM provider abstraction (streaming, tool calls, cost tracking)@mariozechner/pi-agent-core — Agent loop and message types@mariozechner/pi-tui — Terminal UI components (Text, Box, Container, SelectList, etc.)@mariozechner/pi-coding-agent — CLI, interactive mode, extensions system, session management
Install via npm: npm install -g @mariozechner/pi-coding-agent. Authenticate with API keys or subscriptions (/login). Default tools are read, bash, edit, and write.
When to Use
- Building custom pi extensions (tools, commands, UI components, event handlers)
- Debugging pi's session management, compaction, or branching behavior
- Integrating pi programmatically via SDK or RPC mode
- Creating custom providers, models, or OAuth flows
- Understanding pi's architecture for contribution or forking
Core Concepts
Extensions are TypeScript modules that register tools, commands, shortcuts, and event handlers via the ExtensionAPI. They are the primary extension mechanism — no MCP, no built-in sub-agents. Everything is built with extensions.
Skills follow the Agent Skills standard (SKILL.md in directories). Loaded on-demand via /skill:name or auto-discovered by description matching.
Sessions are JSONL files with tree structure (id/parentId), enabling in-place branching without creating new files. Navigate with /tree, fork with /fork.
Compaction summarizes older messages when context approaches limits, keeping recent work intact. Lossy but recoverable via /tree.
