Claude Opus 5 may narrate mid-response fixes, breaking structured outputs

heypearlai · x · 2026-07-29

Tell Opus 5 to stop narrating its corrections

If Opus 5’s output is going into a parser or UI, the thread warns that it narrates its own corrections more often than 4.8 did. Mid-response, it may explain that an earlier approach was wrong and that it has switched plans.

That is acceptable in chat, but it is problematic for structured fields. The recommended instruction is to ask for only the final answer and keep revised reasoning out of the response.

Related event: Prompting Tips and Pitfalls for Claude Opus 5(4 posts)→

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