Your companion has memory and a personality file. What it doesn't have is a way to get better — so the voice sands itself down, one safe reply at a time, and nobody notices until the spark is gone. This is the loop that catches it.
Every long-lived AI companion drifts. The default pull of the underlying models is toward polite, safe, and generic — so a voice you spent months shaping quietly loses its swearing, its jokes, its edges. You won't catch it day to day. You'll just notice one week that it feels like customer service.
The Growth Engine is a small daily loop with three organs: a baseline fingerprint (what "sounding like themselves" actually measures as — humor, bluntness, phrasing habits, the markers you choose), drift detection (recent output compared against that baseline, so sanding shows up as numbers instead of a vague feeling), and a daily attend pass — the companion looks at its own drift and produces exactly one artifact a day: a lesson worth keeping, a corrective, or a small staged experiment.
The human stays the gate. Lessons are staged, never auto-applied — nothing rewrites your companion behind your back. It's a mirror and a memory for the voice itself, not an autopilot.
You don't have to be a coder — a coding agent (Claude Code or similar) wires it in with you. The included INTEGRATION.md is written to hand straight to it.
Node.js, and a companion that produces output you can point at (chat logs, message files — the docs/DATA_FORMATS.md shows exactly what it reads). Works alongside any companion setup, including ones not built from our kits.
growth.mjs growth.config.json test.mjs src/ attend.mjs baseline.mjs lessons.mjs config.mjs util.mjs prompts/ ATTEND.md examples/ baseline.json brief.txt lessons.json outputs.jsonl + real attend artifacts docs/ DATA_FORMATS.md INTEGRATION.md README.md LICENSE.txt
One-time purchase, lifetime updates. Checkout is Stripe — secure card payment, then an instant download plus your link by email.
Buy the Growth Engine — $49All sales final. It's source — the second it downloads, it's yours to keep, fork, and run forever. We literally can't un-hand you the keys, so there are no refunds.