# Claude Mythos 5.1

Model tracker · checked 2026-10-17 · https://dbggr.dev/models/claude-mythos-5-1/

Claude Mythos 5.1 is a frontier model from Anthropic, released 1 September 2026. At Anthropic it costs $10.00 per million input tokens and $50.00 per million output tokens, with a 1M-token context window.

- Made by: Anthropic
- Released: 2026-09-01
- Status: Generally available
- Tier: Frontier
- Weights: Closed
- Context window: 1,000,000 tokens
- Max output: 128,000 tokens
- Input: text, image
- API id: claude-mythos-5-1
- Docs: https://platform.claude.com/docs/en/models/mythos-5-1/overview

## Claude Mythos 5.1 price at Anthropic

US dollars per million tokens. Blended is 3 input tokens for every output token, one number to compare on.

| Provider | Input | Output | Cached input | Blended | Batch | Checked |
|---|---|---|---|---|---|---|
| Anthropic | $10.00 | $50.00 | $0.25 | $20.00 | 50% off | [2026-10-17](https://platform.claude.com/docs/en/about-claude/pricing) |

- Anthropic: Available only to organizations verified through Anthropic's verification programs, such as the Cyber Verification Program; same specifications and pricing as Claude Fable 5.1. Cache writes $12.50 (5 min) or $20 (1 h).

## Models like Claude Mythos 5.1

| Model | Input | Output | Context | Weights |
|---|---|---|---|---|
| Claude Mythos 5.1 | $10.00 | $50.00 | 1M | Closed |
| [Claude Fable 5.1](https://dbggr.dev/models/claude-fable-5-1/) | $10.00 | $50.00 | 1M | Closed |
| [GPT-6 Astra](https://dbggr.dev/models/gpt-6-astra/) | $10.00 | $50.00 | 1.1M | Closed |
| [Claude Opus 5.5](https://dbggr.dev/models/claude-opus-5-5/) | $4.00 | $20.00 | 1M | Closed |
| [Muse Wonder](https://dbggr.dev/models/muse-wonder/) | $4.00 | $20.00 | 1M | Closed |
| [Gemini 4 Argon](https://dbggr.dev/models/gemini-4-argon/) | $2.00 | $10.00 | 1M | Closed |

## FAQ

### How much does Claude Mythos 5.1 cost?

Claude Mythos 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens at Anthropic, and $0.25 per million cached input tokens, with 50% off for batch requests. Prices are list prices in US dollars, last checked 17 October 2026.

### What is Claude Mythos 5.1's context window?

Claude Mythos 5.1 takes up to 1,000,000 tokens in one request and writes up to 128,000 tokens in one response.

### Is Claude Mythos 5.1 open weight?

No. Claude Mythos 5.1 is only available through Anthropic's API; Anthropic doesn't publish the weights.

### Where can I use Claude Mythos 5.1?

Claude Mythos 5.1 is available from Anthropic. At Anthropic, call it as `claude-mythos-5-1`.