pz

A coding-agent harness rewritten from the ground up in Zig. Drop-in replacement for pi — same features, same config, single static binary.

Why pz?

	pi (TypeScript)	pz (Zig)
Binary size	~10 MB + 589 MB node_modules	1.7 MB
Startup time	~430 ms	3 ms
Memory at idle	~153 MB	1.4 MB
Source lines	~139k	~29k
Runtime deps	Node.js / Bun	None
Install	bun install -g	Copy one binary

Features

Full feature parity with pi, plus some extras:

• Interactive TUI — streaming responses, markdown rendering, syntax highlighting
• Image rendering — Kitty graphics protocol support in terminal
• 24 slash commands — /model, /fork, /export, /compact, /share, /tree, and more
• Autocomplete dropdown — fuzzy-filtered command and file path completion
• 8 built-in tools — read, write, edit, bash, grep, find, ls, ask
• Session management — persist, resume, fork, name, export, share as gist
• OAuth + API key auth — automatic token refresh, multi-provider support
• Thinking modes — adaptive and budget-capped extended thinking
• Prompt caching — automatic cache_control on system messages
• Headless modes — --print, --json, and rpc for scripting and integration
• Zero-alloc hot path — rendering and input handling avoid heap allocations
• 582 tests — unit, integration, snapshot, and property tests

Build

Requires Zig 0.15+.

zig build -Doptimize=ReleaseFast

The binary lands in zig-out/bin/pz.

Run

# Uses ~/.pi/agent/auth.json and settings.json automatically
pz

# Explicit provider and model
pz --provider anthropic --model claude-sonnet-4-20250514

# Headless
pz --print "explain this codebase"
echo '{"prompt":"hello"}' | pz --json

Test

zig build test

Changelog

• CHANGELOG.md for release-by-release notes
• pz --changelog or /changelog in TUI for in-app change visibility

Config

pz reads pi's config files directly:

• ~/.pi/agent/auth.json — OAuth / API key credentials
• ~/.pi/agent/settings.json — model, provider, tools, thinking mode
• AGENTS.md / CLAUDE.md — system prompts (project and global)

License

MIT