kimetsu-pi brings Kimetsu — a local-first memory brain for coding agents — to the Pi coding agent.

Coding agents are brilliant and forgetful: every session starts from zero. Kimetsu is a sidecar brain that captures the lessons your agent earns, learns which ones actually help, and hands them back before the next task. The memory pipeline makes no LLM calls — storage and retrieval are 100% local, free, and offline-capable.

Learn more at kimetsu.dev.

What it is

Pi has no MCP layer, so this package brings Kimetsu to Pi through Pi's own extension points:

• Extension (extensions/kimetsu.ts) — a TypeScript Pi extension that hooks Pi lifecycle events (session_start, agent_end, session_shutdown) and shells out to the kimetsu binary to warm, load, and persist brain context around each session. Each call is capped by a timeout, so a slow or hung binary never stalls Pi. If the binary is not on PATH, every hook silently no-ops and Pi is completely unaffected.
• Skill (skills/kimetsu-brain/SKILL.md) — a Pi skill that teaches the agent when and how to consult and record memories during a task.

Why Kimetsu

• Remembers what matters — conventions, failure patterns, the exact command that regenerates your schema. Captured once, retrieved by meaning.
• Speaks first — proactive session-start digests, episodic resumes, and pre-task context, so the agent's first turn already knows your repo.
• Learns what helps — cited memories get promoted; stale advice decays and is pruned.
• Model-free retrieval — FTS5 + local embeddings + local reranking. Zero API cost, works offline.
• Stays yours — one SQLite file per project. No cloud, no vector DB, no telemetry. Back it up with cp.

Benchmarks

89.4%	LoCoMo, the long-conversation memory benchmark
83.0%	LongMemEval, the public long-term-memory benchmark
73.3%	BEAM 100K memory benchmark
13×	cheaper per solved task ($0.19 vs $2.47 on a Terminal-Bench slice)
~1M	memories in ~3 GB RAM with sub-2s retrieval, one SQLite file

Prerequisite

The kimetsu binary must be on PATH. Install it with:

npm install -g kimetsu-ai

or via cargo or a prebuilt archive — see the install guide for all options. If the binary is absent, the extension silently no-ops and Pi is unaffected.

Install

pi install npm:kimetsu-pi

What it does on each event

Pi lifecycle event	Kimetsu command run
session_start	kimetsu brain warm then kimetsu brain context-hook
agent_end	kimetsu brain stop-hook
session_shutdown	kimetsu brain session-end-hook

Development

npm install
npm test
npm run typecheck

Links

• Website & docs: kimetsu.dev
• Main project: github.com/RodCor/kimetsu

License

MIT OR Apache-2.0