PiG Released: Go Port of Pi Coding Agent Harness with 21ms Startup

PiG is a direct port of the Pi coding agent harness, rewritten in Go to provide a single static binary for macOS, Linux, and Windows. The port replicates Pi’s agent loop, terminal UI, session management, and provider integrations while eliminating the Node.js dependency for core operations.

Performance and Architecture

The Go implementation delivers significant performance improvements over the original Node.js-based Pi:

• Startup Time: Measured at approximately 21 ms, compared to Pi’s median of 300 ms.
• Memory Usage: Consumes about one-quarter of Pi’s peak memory.
• Extension Support: Existing Pi extensions run unchanged. New extensions can be written in Go (in-memory pipes), or other languages like TypeScript, Python, and Rust (supervised subprocesses over local sockets).

Verification and Availability

The project includes rigorous verification against the upstream Pi codebase:

• TUI Fidelity: Width handling was ported from Pi’s algorithm and validated via differential tests against Pi’s code over ~1.5 million cases.
• Behavioral Testing: Real-terminal scenarios (tmux-driven) compare screen outputs to ensure behavioral parity.

PiG is available via go install, a curl installer, or npm (npm i -g u/pi-in-go). The project is open-source, with much of the initial porting assisted by AI agents, though final shipping decisions rely on human review and automated tests.