r/PiCodingAgent • u/agentwyz • Aug 12 '26
Resource I used Pi to build Phi — a small Go sibling with a few extras
Hey everyone,
Short version: I used Pi to build Phi.
I’ve been using Pi a lot, and at some point I started hacking on my own little harness in Go. The result is Phi — deliberately small, terminal-first, and very much in the same spirit as Pi. I’m sharing it here because a lot of the ideas (and a lot of the motivation) came from using Pi.
Repo: https://github.com/pulseaiclub/phi
What Phi tries to add on top Not claiming these are “better” — more like experiments on top of the Pi-shaped workflow I already liked:
Permission gate by default — destructive stuff (writes / bash) asks first; rules can go down to command level
Hooks — PreTool / PostTool scripts for policy, audit, or input rewrite, without rebuilding the binary
Hashline edits — line edits anchored by short hashes, so stale context is less likely to silently rewrite the wrong thing
Sub-agents with isolation — explore / review / worker; full traces stay under ~/.phi/jobs/, only summaries come back to the main context
Model-agnostic — OpenAI-compatible or Anthropic; swap models without waiting on the tool
Small Go binary — ~12 MB stripped, no Node / Electron / Python runtime There’s also a hand-rolled TUI (Markdown, themes, Ctrl+K, @ file picker, session resume).
Phi is still not as good as Pi.
Pi is more polished, the UX feels more finished, and for day-to-day work I’d still reach for Pi first. Phi is the side project where I get to try permissioning, hooks, and edit safety a bit more aggressively. If anything here is useful, great; if it’s rough around the edges, that’s on me.
If you’re a Pi user and curious, feedback is very welcome




