AHA!: weight-space programming with no LLM lifts Qwen3.5-0.8B GSM8K from 14.0 to 71.2

hbouammar · x · 2026-11-16

AHA! is self-supervised weight-space programming that needs no external LLM at any stage: a rank-one edit to two weight matrices, derived purely from the model's own samples plus a linear program, stops a small reasoning model from looping until it exhausts tokens. No agent, no gradients, no training run.

Held-out results (unedited → edited):

On the 0.8B it matches the edit made by a frontier weight-reading agent; on the 2B nothing is inherited. The authors also report failures: the direction best separating looping from productive text yields the worst edit. Code is open source under MIT. Builds on MIT CSAIL's Sparks of Weight-Space Programming, with the novelty that every input now comes from the model's own outputs.

Original post →

More from Models

Models channel →