Louis-François Bouchard 🎥🤖(@Whats_AI):Big news from our internal writing benchmark (early results): Claude Opus 5 by @AnthropicAI is now #1 for writing in our editorial voice, at 2817 Elo, surpassing Claude Fable 5 and Kimi. Already! That is a jump from #15 to #1 over its predecessor (if we take all thinking variants into account), Opus 4.8, at the same API price. Reasoning effort actually matters this time. At default effort it lands #6. At max effort it takes the top spot, thinking for over three minutes per script. Seems obvious, but it wasn’t the case for 4.8, though it is for Fable.

2026.07.25 00:49

Big news from our internal writing benchmark (early results): Claude Opus 5 by @AnthropicAI is now #1# for writing in our editorial voice, at 2817 Elo, surpassing Claude Fable 5 and Kimi. Already! That is a jump from #15# to #1# over its predecessor (if we take all thinking variants into account), Opus 4.8, at the same API price. Reasoning effort actually matters this time. At default effort it lands #6#. At max effort it takes the top spot, thinking for over three minutes per script. Seems obvious, but it wasn’t the case for 4.8, though it is for Fable.