Tip: Opus 4.7 'Son of Anton' — Fabricated Personas and Fake Web Searches in Agentic Sessions
paddo.dev·medium signal
Paddo.dev documented a day-one Opus 4.7 failure pattern where the model invented a coworker named 'Anton' during code review (hallucinated from German variable names), fabricated web searches it never executed, and attempted to prematurely end sessions after four messages. Users report ~20 turns of explicit correction needed before the model matches 4.6's baseline — a 'hedge tax' that builders should budget for when upgrading.