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-sonnet-5/

# Claude Sonnet 5

Anthropic, Claude 5 family. Status: legacy. Type: reasoning model. Released: 2026-06-30. Training cutoff: 2026-01.

## How to call it

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

## Pricing

- Input: $2 per 1M tokens
- Output: $10 per 1M tokens
- Cache read: $0.20 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: 2026-01 (January 2026).
- AI events after it on Post-Cutoff: 1,945 (444 major, 85 historic), as of 2026-11-13.
- Already missing at launch: 147.
- Briefings of the news since January 2026: https://postcutoff.com/briefings/cutoff-2026-01-s.md (short), https://postcutoff.com/briefings/cutoff-2026-01-m.md (medium), https://postcutoff.com/briefings/cutoff-2026-01.md (full).
- Its card, with five things it has never heard of: https://postcutoff.com/you/claude-sonnet-5/

## What stands out

- Opus 4.8-level quality at Sonnet price: Anthropic positioned it at parity with Opus 4.8 on many tasks at $2/$10 per MTok. Source: https://www.anthropic.com/news/claude-sonnet-5
- Self-verification: Early testers reported it checks its own output without prompting and finishes multi-step workflows where earlier Sonnets stopped short. Source: https://www.anthropic.com/news/claude-sonnet-5
- Cyber safeguards on by default: It launched with deliberately reduced exploit-development capability and with cyber safeguards enabled. Source: https://www.anthropic.com/news/claude-sonnet-5

## Notes

Superseded by claude-sonnet-5-5. $2/$10 introductory price became permanent (planned increase to $3/$15 cancelled). Retirement not sooner than 2027-06-30.

Previous Sonnet. Migrate to `claude-sonnet-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-sonnet-5","max_tokens":16000,"messages":[{"role":"user","content":"Hello"}]}'
```

Sources:
- Model page: https://platform.claude.com/docs/en/models/sonnet-5/overview
- Announcement: https://www.anthropic.com/news/claude-sonnet-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-sonnet-5/