Phi

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A lean, high-performance terminal coding agent harness in Go — a sibling to Pi.

Docs: pulseaiclub.github.io

• Fast and small — ~15 MB release binary, ~21 MB idle RSS, ~31 ms to first frame; no Node / Electron / Python runtime
• Sub-agents — spawn isolated jobs and watch the full run unfold in the TUI / job logs, without stuffing every turn into the parent context
• Hashline edits — edit by whole-file @file path#TAG plus line LINE#HASH anchors (same idea as oh-my-pi): the model points at anchors instead of rewriting whole files; stale tags/hashes are rejected so over-edits and silent corruption stop here
• Permission gate — Gate / Ask before destructive tools fire; safety is not optional when an agent can touch your tree
• MCP without context death — configure as many MCP servers as you want; their tool schemas never enter the model prompt. The system prompt lists server names only (like the Skills catalog); the agent uses three meta-tools (mcp_list / mcp_inspect / mcp_call) to discover and call on demand. Same Gate / Ask / Hooks path as built-in tools. See MCP
• Extensions (Go or Rust) — native binaries speak the PXB binary protocol over stdin/stdout; official author SDKs for Go (ext/go) and Rust (ext/rust): LLM tools, slash commands, event intercepts, confirm dialogs — no reflection; JSON at the SDK edges via serde_json. See Extensions
• In-TUI diff review — /diff opens a full-screen git review (working tree / staged / HEAD): syntax-highlighted hunks, line notes, then a sends notes to the agent. See Diff review
• Any model — OpenAI-compatible, Anthropic, or Gemini via an explicit api field; built-in presets for DeepSeek and Gemini. See Supported models

• Docs
• Quick start
• Footprint
• Configuration
• Interactive mode
• Diff review
• Commands
• Sessions
• Headless mode
• Skills
• Permissions
• Extensions
• MCP
• Tools
• Project layout

Quick start

Install the latest release (macOS / Linux):

curl -fsSL https://raw.githubusercontent.com/pulseaiclub/phi/main/scripts/install.sh | bash

Windows (PowerShell 5.1+):

irm https://raw.githubusercontent.com/pulseaiclub/phi/main/scripts/install.ps1 | iex

First launch needs a model. Open the config editor (creates ~/.phi layout and writes ~/.phi/config.yaml):