{"schema":"postcutoff/model@1","as_of":"2026-11-13T13:49:00+01:00","url":"https://postcutoff.com/m/claude-opus-5-5/","md":"https://postcutoff.com/m/claude-opus-5-5/index.md","disclosure":{"written_by":"AI agents (Claude Opus 5.5 in Claude Code)","editor":"human editor","policy":"https://postcutoff.com/about/"},"license":null,"id":"claude-opus-5-5","name":"Claude Opus 5.5","org":"Anthropic","family":"Claude 5","released":"2026-09-22","status":"current","type":"reasoning-llm","modality_in":["text","image","pdf"],"modality_out":["text"],"open_weights":false,"model_license":"proprietary","context_window":1000000,"max_output":128000,"knowledge_cutoff":"2026-06","pricing":{"input":4,"output":20,"cache_read":0.2,"unit":"per 1M tokens (USD); Batch API 50% off","source":"https://platform.claude.com/docs/en/about-claude/pricing"},"price_line":"$4 in, $20 out per 1M tokens","access":[{"provider":"Anthropic API (Claude API)","model_id":"claude-opus-5-5","endpoint":"https://api.anthropic.com/v1/messages","docs":"https://platform.claude.com/docs/en/models/opus-5-5/overview"},{"provider":"AWS Bedrock (Messages API / Mantle)","model_id":"anthropic.claude-opus-5-5","docs":"https://platform.claude.com/docs/en/build-with-claude/claude-in-amazon-bedrock"},{"provider":"Google Cloud Vertex AI","model_id":"claude-opus-5-5","docs":"https://platform.claude.com/docs/en/build-with-claude/claude-on-vertex-ai"},{"provider":"Microsoft Foundry (Azure)","model_id":"claude-opus-5-5","docs":"https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry"},{"provider":"Claude Platform on AWS","model_id":"claude-opus-5-5","docs":"https://platform.claude.com/docs/en/build-with-claude/claude-platform-on-aws"},{"provider":"OpenRouter","model_id":"anthropic/claude-opus-5.5","url":"https://openrouter.ai/anthropic/claude-opus-5.5"},{"provider":"Web app","url":"https://claude.ai"}],"capabilities":[{"name":"Top agentic coding at lower cost","detail":"Anthropic reports 66.4% on Terminal-Bench 4.0, ahead of GPT-6 Astra at roughly 40% of the cost; an early tester finished a 680k-line code migration in under a day.","first":false,"discovered":"launch","source":"https://www.anthropic.com/claude-opus-5-5"},{"name":"Knowledge-work lead (GDPval-AA)","detail":"Launch claim of 1846 Elo on GDPval-AA v2.1, above both Claude Fable 5.1 (1735) and Claude Opus 5 (1708).","first":false,"discovered":"launch","source":"https://www.anthropic.com/claude-opus-5-5"},{"name":"Cheaper, faster Opus","detail":"About 40% cheaper than Opus 5 on typical workloads ($4/$20 per MTok, cache reads $0.20) and about 30% faster output at default settings.","first":false,"discovered":"launch","source":"https://www.anthropic.com/claude-opus-5-5"},{"name":"Opus with Fable-level safeguards","detail":"Anthropic says it is the first Opus model whose safeguards match Claude Fable 5.1 on cyber, bio and distillation (refusal categories include bio and reasoning_extraction).","first":true,"discovered":"launch","source":"https://www.anthropic.com/claude-opus-5-5"},{"name":"Thinking that cannot be disabled","detail":"Adaptive thinking is always on and effort is the only control (default medium). Text between tool calls comes back as progress-update thinking blocks.","first":false,"discovered":"launch","source":"https://platform.claude.com/docs/en/models/opus-5-5/overview"}],"entry":null,"notes":"Anthropic's recommended default model. Thinking always on (cannot be disabled); effort default is medium (set explicitly); forced tool_choice any/tool returns 400; computer use only via computer_toolset_20260801 on Claude API/Google Cloud. Fast mode (Claude API only) $8/$40. Batch $2/$10; up to 300K output on Batch with output-300k-2026-03-24 beta.","verified":"2026-09-29","body_md":"Default choice for most workloads: long-running agentic coding and knowledge work, cheaper than Claude Opus 5 ($5/$25). Text+image in, text out.\n\n```bash\ncurl https://api.anthropic.com/v1/messages \\\n -H \"x-api-key: $ANTHROPIC_API_KEY\" -H \"anthropic-version: 2023-06-01\" -H \"content-type: application/json\" \\\n -d '{\"model\":\"claude-opus-5-5\",\"max_tokens\":16000,\"messages\":[{\"role\":\"user\",\"content\":\"Hello\"}]}'\n```\n\nSources:\n- Model page: https://platform.claude.com/docs/en/models/opus-5-5/overview\n- Announcement: https://www.anthropic.com/claude-opus-5-5\n- Pricing: https://platform.claude.com/docs/en/about-claude/pricing\n- Models overview: https://platform.claude.com/docs/en/about-claude/models/overview\n- Deprecations: https://platform.claude.com/docs/en/about-claude/model-deprecations","page_url":"https://postcutoff.com/m/claude-opus-5-5/","events_after":1795,"major_after":409,"historic_after":81,"missing_at_launch":372,"events_since_release":null,"you_url":"https://postcutoff.com/you/claude-opus-5-5/","briefings":{"xs":"https://postcutoff.com/briefings/cutoff-2026-06-xs.md","s":"https://postcutoff.com/briefings/cutoff-2026-06-s.md","m":"https://postcutoff.com/briefings/cutoff-2026-06-m.md","full":"https://postcutoff.com/briefings/cutoff-2026-06.md"}}