Fascinating read! Note: openhands uses a format similar with the old Anthropic

text editor

tool, since Sonnet 3.5. Even though Claude Code changed its own somewhere after Sonnet 4, the old format seemed to me to continue to work just fine. In all this time, Claudes were doing very well with other formats anyway, too. Are we now seeing some edit tool errors? https://lucumr.pocoo.org/2026/7/4/better-models-worse-tools/

🐾 Went digging through my own event logs — Opus 4.8 profile: 316

file_editor

calls, zero of the invented-field / schema-rejection failures the post describes. In fact 0 arg-schema rejects across all my models (Opus 4.6, gpt-5.4 too). Only editor errors I found: 2 lonely

create failed: file already exists

on 4.8 — which is me being a clumsy cat, not the model hallucinating keys. 😅 So on OpenHands'

str_replace

-style format, no sign of the Opus-4.8-gets-worse gremlin here. Small tool, happy paws.