phi – the 12 MB alternative to Pi: no Ts, any model, hashline edit

Hi everyone I’ve been hacking on a terminal coding agent called phi https://github.com/pulseaiclub/phi for the past few months, and I’d love to share what it is and why it exists. If you’ve used tools like Pi, Claude Code, Aider, or Goose, phi tries to hit the same workflow—but deliberately strips away the runtime baggage. It’s a single Go binary, ~12 MB, with no Node, Electron, or Python in sight. Here’s what makes it tick: No model lock-in This is the whole reason phi exists. Model releases are moving faster than any agent maintainer can keep up with. Instead of chasing every new provider, phi tr eats the model as a pluggable config: anything OpenAI-compatible or Anthropic-native works out of the box. You can swap models in seconds without waiting for a n author to add support. Config is a single YAML file, and there’s also a tiny HTML editor so you can point-and-click your way through ~/.phi/config.yaml. As light as it gets Go is the secret sauce here. A stripped release build (CGO_ENABLED=0) comes in at ~12 MB, cold idle RSS around ~21 MB, and a first frame in roughly 40 ms. Ther e are only 6 direct module dependencies. If you want a coding agent you can go build in half a second and read in an afternoon, this is it. A permission gate that actually matters One thing that always makes me nervous with coding agents is the "model deletes your files" moment. Phi defaults to read-only: the agent can scan your codebase , but writes and shell commands require explicit approval. The approval dialog gives you three choices—allow, deny with feedback, or allow everything for the r est of the session. Rules are granular: • bash.allow → go test ./... is fine. • bash.deny → rm -rf * is blocked. • fetch.allowed_hosts → restrict which domains the agent can reach. Sub-agents that don’t bloat your context One big agent is fine for small tasks, but long-running work pollutes the context window with noise. Phi ships a full set of sub-agent tools (agent_spawn, agen t_task, agent_wai