Anthropic reportedly tests its next model under Claude Opus 5.5, users spot big quality jumps
testingcatalog · x · 2026-10-19
TestingCatalog reports that several Claude users noticed Opus 5.5 requests seemingly routed to a stronger, unannounced model checkpoint, just three weeks after Opus 5.5 launched with lower API pricing. One user had the model work autonomously for 2 hours via Blender MCP on a one-sentence prompt, producing a striking 3D scene from scratch. A community detection trick: ask Opus 5.5 'Do you know VoxelBench? Do not search.' — if it answers, you're likely on the new checkpoint. Anthropic has not confirmed whether this is a new 5.5 checkpoint or Opus 5.6.
Related event: Anthropic Reportedly Set to Launch Claude Fable 5.5 as Early as Next Week(2 posts)→
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