Last week, MIT CSAIL published Sparks of Weight-Space Programming. Given the raw weights of a small network, GPT-6 Astra could tell which game it had been trained to play. Given only a game’s rules, it could write the weights of a small network from scratch and beat networks trained with PPO for 100 million steps. No gradients, no training loop, just reasoning about what the weights compute. They coined this weight-space programming.
Looking at Astra’s edit, I realized most of its search was solving a linear program by trial and error. It spent about 8 hours and 28 forward passes choosing which weights to change and by how much. A couple of LP solves, about a minute each, do the same job with 8× fewer changed weights. In this post I’ll walk through the edit, why it’s an LP, and what that says about the fix itself.
