How does Claude Opus 5's self-verification behavior differ from Claude Opus 4.8?

Claude Opus 5 verifies its own work unprompted more consistently than Opus 4.8 did, meaning it's more likely to catch and correct its own mistakes without an explicit instruction telling it to double-check.

This creates a specific migration trap: verification instructions written for Opus 4.8, like an explicit "double-check your work" line, now compound with Opus 5's own built-in verification behavior, causing over-verification that spends extra tokens without adding proportional value.

Anthropic's own prompting guidance recommends removing global double-check instructions when migrating, and only scoping an explicit verification instruction to a specific step if that particular step genuinely still needs one, rather than applying it as a blanket rule the way it may have been useful on Opus 4.8.

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