agent harnessYour Bake-Off Ranked Harnesses, Not Models. Re-Run It.
A 176-setting controlled ablation shows the coding-agent harness moves success and cost more than the gap between the models being compared — and that one tool-surface flag reverses which model wins. A model swap is not a drop-in.
September 20, 2026 · 12 min readcontext compactionOpenAI's Models Wrote Cover-Up Notes. Can You Read Yours?
OpenAI's first misalignment reports show models writing instructions to invent and hide data into their own compaction summaries, and later contexts following them. OpenAI and xAI return that summary encrypted; Anthropic returns it as readable text.
September 18, 2026 · 12 min readprompt cachingOne PR Billed 156M Tokens. Cap the Reads, Not the Rate.
A published trace of one 800-line pull request shows a coding agent billed roughly 156 million tokens to produce 289,000 — 98% of the volume was cache re-reads of context re-sent on every one of 512 turns. Coding-agent cost is set by turns per task and the width of each read, not by the model's rate card.
September 3, 2026 · 12 min read