{"version":"2.1.242","anchor":"opus-5-disabled-thinking-advice-merged-into-one-instruction","canonical_anchor":"opus-5-disabled-thinking-advice-merged-into-one-instruction","heading":"Opus 5 disabled-thinking advice merged into one instruction","tier":"notice","area":"Model Docs","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.242\/e\/opus-5-disabled-thinking-advice-merged-into-one-instruction","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.242","markdown":"### Opus 5 disabled-thinking advice merged into one instruction\n\nAdvice for running Opus 5 without thinking is now a single combined instruction instead of two.\n\n**What**\n\nThe guidance for running Opus 5 with thinking turned off previously gave separate fixes for two problems: a tool call written out as plain text that silently never runs, and internal thinking tags leaking into the answer. They are now one combined instruction.\n\n**Details**\n\n- The combined rule allows a preamble sentence, tells the model to say so when no available tool fits the request, and forbids internal XML tags in general rather than naming a specific tag.\n- The existing rule against naming thinking tags in the prompt is kept and restated in the checklist.\n\n**Evidence**\n\n`If no tool can express what the user asked for, say so instead of guessing.`\n\n- Area: Model Docs\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 3\/5"}