YOUR LLM DOESN'T WRITE CORRECT CODE. IT WRITES PLAUSIBLE CODE.

Summary from the TLDR AI newsletter

A benchmarked LLM-generated Rust rewrite of SQLite ran 20,171x slower on primary key lookups because the query planner never checked the is_ipk flag, sending every WHERE clause through a full table scan instead of a B-tree search. The same author's disk cleanup daemon came in at 82,000 lines with a Bayesian scoring engine and PID controller to solve a problem that a one-line cron job already handles. The root failure is structural: LLMs optimize for plausible output matching the user's intent, and METR's RCT with 16 experienced open-source developers confirmed the problem scales, finding AI users were 19% slower while believing they were 20% faster.