kernels
OpenAI says GPT-5.6 Sol autonomously rewrote the code that serves it, cutting serving costs 20% News
OpenAI published an engineering account on July 29 saying GPT-5.6 Sol, working through Codex, autonomously rewrote its production GPU kernels and redesigned its own draft model, contributing to a 20% cut in end-to-end serving cost and a 15% gain in token-generation efficiency.
FpSan (Floating-Point Sanitizer) Tool
Open-source correctness checker for Triton GPU kernels, and the tool OpenAI says it used to validate the production kernels GPT-5.6 Sol rewrote. It compares symbolic computation under its own payload algebra rather than simulating IEEE floating point, so results should be compared only against other FpSan runs. Useful for anyone writing or generating custom kernels who needs to catch numerical breakage before it reaches production.
FlashKDA Tool
Moonshot AI's MIT-licensed kernel implementation of Kimi Delta Attention, the linear-attention mechanism underneath Kimi K3, published ahead of the model weights themselves. Useful today for anyone building or serving bounded-state attention rather than a growing key-value cache.