Claude Mythos 5
Specs and pricing identical to Fable 5, but shipped without the safety classifiers that gate high-risk cybersecurity and bio requests. Access is limited to Project Glasswing participants — vetted critical-infrastructure and government partners — so it is listed here for completeness rather than as a general option.
Pricing checked against provider documentation on . How we verify
claude-mythos-5 reasoning Access to this model is restricted and cannot be obtained through the standard API. It is listed for completeness.
Input
$10.00
/ 1M tokens
Output
$50.00
/ 1M tokens
Context
1M
1,000,000 tokens
Max output
128K
tokens per request
Pricing caveat: Same price as Fable 5. Access restricted to Project Glasswing partners.
What it costs in practice
A workload of 10M input and 2M output tokens per month — roughly a moderately busy production assistant — runs $200.00/month on Claude Mythos 5. Routing that same volume through the batch API brings it to $100.00. The next cheaper option, Claude Opus 5 , would cost $100.00.
Where Claude Mythos 5 fits
- Vetted offensive-security research
- Critical infrastructure defence
Specifications
- API model ID
- claude-mythos-5
- Provider
- Anthropic
- Model family
- Claude 5
- Released
- June 2026
- Knowledge cutoff
- January 2026
- Context window
- 1,000,000 tokens
- Max output
- 128,000 tokens
- Native reasoning
- Yes
- Relative latency
- high
- Input modalities
- text, image
- Output modalities
- text
- Open weights
- No
- Cached input
- $1.00 / 1M tokens
- Batch discount
- 50%
Frequently asked
How much does Claude Mythos 5 cost?
Claude Mythos 5 costs $10.00 per million input tokens and $50.00 per million output tokens, with cached input at $1.00. Batch processing is 50% cheaper.
What is Claude Mythos 5's context window?
Claude Mythos 5 accepts up to 1,000,000 tokens of context and can generate up to 128,000 output tokens per request.
Is Claude Mythos 5 a reasoning model?
Yes. Claude Mythos 5 performs native chain-of-thought before answering. Those thinking tokens are billed at the output rate, so budget above the sticker price.
What is Claude Mythos 5 best for?
Vetted cyber-defence work only. Specs and pricing identical to Fable 5, but shipped without the safety classifiers that gate high-risk cybersecurity and bio requests. Access is limited to Project Glasswing participants — vetted critical-infrastructure and government partners — so it is listed here for completeness rather than as a general option.