GPT-5.6 Benchmarks Explained: Beyond the Leaderboard Numbers
OpenAI's GPT-5.6 launched without a score on the tracked SWE-bench Verified board, and the numbers that do exist swing wildly by who runs the test. BenchLM's July 2026 tracking puts Sol at 64.6% on SWE-bench Pro against Claude Fable 5's 80.3%, a figure that is scaffold-dependent and partly self-reported. The gap says less about the model than about the collapse of shared benchmarks as a buying signal. For PMs, the practical move is to stop reading leaderboards and run a small eval on your own workload instead.