As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/m/claude-opus-5/

# Claude Opus 5

Anthropic, Claude 5 family. Status: legacy. Type: reasoning model. Released: 2026-07-24. Training cutoff: 2026-05.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| Anthropic API (Claude API) | `claude-opus-5` | https://api.anthropic.com/v1/messages | https://platform.claude.com/docs/en/models/opus-5/overview |
| AWS Bedrock (Messages API / Mantle) | `anthropic.claude-opus-5` |  | https://platform.claude.com/docs/en/build-with-claude/claude-in-amazon-bedrock |
| Google Cloud Vertex AI | `claude-opus-5` |  | https://platform.claude.com/docs/en/build-with-claude/claude-on-vertex-ai |
| Microsoft Foundry (Azure) | `claude-opus-5` |  | https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry |
| Claude Platform on AWS | `claude-opus-5` |  | https://platform.claude.com/docs/en/build-with-claude/claude-platform-on-aws |
| OpenRouter | `anthropic/claude-opus-5` |  | https://openrouter.ai/anthropic/claude-opus-5 |
| Web app |  |  | https://claude.ai |

## Pricing

- Input: $5 per 1M tokens
- Output: $25 per 1M tokens
- Cache read: $0.50 per 1M tokens
- Unit as published: per 1M tokens (USD); Batch API 50% off
- Source: https://platform.claude.com/docs/en/about-claude/pricing
- Last checked: 2026-09-29

## Specs

- Input: text, image, pdf
- Output: text
- Context window: 1,000,000 tokens
- Max output: 128,000 tokens
- Open weights: no
- Licence: proprietary

## What it has not seen

- Published training cutoff: 2026-05 (May 2026).
- AI events after it on Post-Cutoff: 1,829 (419 major, 82 historic), as of 2026-11-13.
- Already missing at launch: 95.
- Briefings of the news since May 2026: https://postcutoff.com/briefings/cutoff-2026-05-s.md (short), https://postcutoff.com/briefings/cutoff-2026-05-m.md (medium), https://postcutoff.com/briefings/cutoff-2026-05.md (full).
- Its card, with five things it has never heard of: https://postcutoff.com/you/claude-opus-5/

## What stands out

- Novel problem solving (ARC-AGI 3): Anthropic says it scored about 3x as high as competing models on ARC-AGI 3. Source: https://www.anthropic.com/news/claude-opus-5
- Near-Fable coding at half the price: Launch claim: more than doubles Opus 4.8 on Frontier-Bench and beats Fable 5 on OSWorld 2.0 at about a third of the cost. Source: https://www.anthropic.com/news/claude-opus-5
- Self-built tooling: In one demo it wrote its own vision pipeline to solve a FreeCAD reconstruction task. Source: https://www.anthropic.com/news/claude-opus-5
- Thinking on by default (first): First Opus where omitting the thinking parameter runs adaptive thinking. Source: https://platform.claude.com/docs/en/models/opus-5/overview

## Notes

Superseded by claude-opus-5-5 (cheaper). Thinking on by default; {type: disabled} allowed only at effort high or below. Fast mode $10/$50 (Claude API only). Retirement not sooner than 2027-07-24.

Previous Opus. Migrate to `claude-opus-5-5`.

```bash
curl https://api.anthropic.com/v1/messages \
 -H "x-api-key: $ANTHROPIC_API_KEY" -H "anthropic-version: 2023-06-01" -H "content-type: application/json" \
 -d '{"model":"claude-opus-5","max_tokens":16000,"messages":[{"role":"user","content":"Hello"}]}'
```

Sources:
- Model page: https://platform.claude.com/docs/en/models/opus-5/overview
- Announcement: https://www.anthropic.com/news/claude-opus-5
- Pricing: https://platform.claude.com/docs/en/about-claude/pricing
- Models overview: https://platform.claude.com/docs/en/about-claude/models/overview
- Deprecations: https://platform.claude.com/docs/en/about-claude/model-deprecations

Model page: https://postcutoff.com/m/claude-opus-5/