Claude Mythos 5.1
No shutdown before this date. Claude Mythos 5.1 stays on the Claude API until at least Sep 1, 2027.
≥ 11 mo- Earliest retirement
- ≥ 322 daysSep 1, 2027 · Claude API
- List price · $ per 1M
- $10.00 in $50.00 outClaude API · cached input $0.25
- Context window
- 1MMax output 128K tokens
- Released
- Sep 1, 2026Anthropic
Dates on every platform
| Platform | Model ID and status | Deprecated | Shuts down | Replacement |
|---|---|---|---|---|
| Claude APIAnthropic: Model deprecations (opens in a new tab) · checked Oct 14, 2026 | claude-mythos-5-1Active | – | ≥ 11 moNot sooner than | – |
| Azure AI FoundryMicrosoft: Model retirement schedule - Microsoft Foundry (opens in a new tab) · checked Oct 14, 2026 | claude-mythos-5-1:1Preview | – | None set | – |
| Amazon BedrockAmazon Web Services: Amazon Bedrock model card: Claude Mythos 5.1 (opens in a new tab) · checked Oct 14, 2026 | anthropic.claude-mythos-5-1Active · also global.anthropic.claude-mythos-5-1, us.anthropic.claude-mythos-5-1 | – | ≥ 11 moNot sooner than | – |
| Google Vertex AIAnthropic: Claude on Google Cloud Agent Platform (opens in a new tab) · checked Oct 14, 2026 | claude-mythos-5-1Active | – | None set | – |
Available only to organizations verified through Anthropic programs such as the Cyber Verification Program.
Version 1 runs on Anthropic infrastructure.
Anthropic lists it on Google Cloud with limited availability to verified organizations.
What breaks when you move off Claude Mythos 5.1
No breaking changes are recorded for Claude Mythos 5.1.
List prices
| Platform | Input | Cached | Output | In effect | Source |
|---|---|---|---|---|---|
Claude APIclaude-mythos-5-1 | $10.00 | $0.25 | $50.00 | Sep 1, 2026Current | Anthropic: Pricing (opens in a new tab) |
Amazon Bedrockanthropic.claude-mythos-5-1 | $11.00 | $0.275 | $55.00 | Sep 1, 2026Current · Standard tier, in-Region or geographic cross-Region inference, which Bedrock prices 10% above global cross-Region inference. | Amazon Web Services: AWS Price List API: AmazonBedrockFoundationModels, us-east-1 (opens in a new tab) |
Change history
ReleaseClaude Mythos 5.1 released for verified organizationsClaude API
Claude Mythos 5.1 offers the capabilities of Claude Fable 5.1 to organizations verified through Anthropic programs.
- Platform
- Claude API
- Model
- Claude Mythos 5.1
Source: Anthropic, Claude Mythos 5.1 (opens in a new tab); Anthropic, Claude Fable 5.1 and Claude Mythos 5.1 migration guide (opens in a new tab)
ReleaseClaude Mythos 5.1 available on Amazon BedrockAmazon Bedrock
Bedrock added Claude Mythos 5.1 as anthropic.claude-mythos-5-1.
- Platform
- Amazon Bedrock
- Model
- Claude Mythos 5.1
Source: Amazon Web Services, Amazon Bedrock model card: Claude Mythos 5.1 (opens in a new tab)