Opus 5.5 thinking is always on: medium effort rivals high-effort Opus 5, says Anthropic
FinanceYF5 · x · 2026-10-29
Opus 5.5 no longer supports disabling thinking — old prompts that turned it off or forced visible reasoning no longer work, so start at low effort and drop reasoning-extraction instructions. Also avoid max thinking effort everywhere: medium effort matches or beats high-effort Opus 5 on many tasks; only use xhigh/max where clearly better.
Related event: Anthropic Releases Claude Opus 5.5 Prompting Guide with 11 Best Practices(25 posts)→
More from coding & agent
- Open-Source Orinyx Launches MCP Tool to Independently Verify Healthcare AI Agent Outputs — Practical_Green5775 · 2026-10-29
- DHH: AI Tools Could Make the Best-vs-Worst Programmer Gap 1,000x — tristanbob · 2026-10-29
- Open-Source Stackchan Desk Robot Chats, Dances and Shows Memes — Full Build Guide Included — alexcovo_eth · 2026-10-29
- Addy Osmani: You're overprompting Claude — one goal plus a check beats prompt bloat — addyosmani · 2026-10-29
- Teach Hermes OPNsense docs with /learn, get an optimized firewall in 15 minutes — Teknium · 2026-10-29
- Interactive ghost story built on Gemma 4 stress-tested with 478 adversarial prompts — Extreme_Ad5709 · 2026-10-29