Claude Fable 5.1
No shutdown before this date. Claude Fable 5.1 stays on Google Vertex AI until at least Mar 1, 2027.
≥ 5 mo- Earliest retirement
- ≥ 138 daysMar 1, 2027 · Google Vertex AI
- Arena Text
- 1,501#6 of 128 · Arena
- Arena WebDev
- 1,744#5 of 69 · Arena
- List price · $ per 1M
- $10.00 in $50.00 outClaude API · cached input $0.25
- Context window
- 1MMax output 128K tokens
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-fable-5-1Active | – | ≥ 11 moNot sooner than | – |
| Azure AI FoundryMicrosoft: Model retirement schedule - Microsoft Foundry (opens in a new tab) · checked Oct 14, 2026 | claude-fable-5-1:1Preview | – | ≥ 14 moNot sooner than | – |
| Amazon BedrockAmazon Web Services: Amazon Bedrock ListFoundationModels, us-east-1 (opens in a new tab) · checked Oct 14, 2026 | anthropic.claude-fable-5-1Active · also global.anthropic.claude-fable-5-1, us.anthropic.claude-fable-5-1 | – | ≥ 11 moNot sooner than | – |
| Google Vertex AIGoogle Cloud: Claude Fable 5.1 on Google Cloud (opens in a new tab) · checked Oct 14, 2026 | claude-fable-5-1Active | – | ≥ 5 moNot sooner than | – |
Version 1 runs on Anthropic infrastructure.
Preview dates on Azure are a floor. Preview deployments are upgraded to a newer version or retired with at least 30 days' notice.
In us-east-1, requests go through a cross-Region inference profile (listed in aliases).
What breaks when you move off Claude Fable 5.1
- Parameters
- Behavior
- Availability
Intelligence
| Benchmark | Publisher | Score | Rank | Published |
|---|---|---|---|---|
| Arena Text | Arena | 1,501 ± 3 | #6 of 128 | Oct 8, 2026 |
| Arena WebDev | Arena | 1,744 ± 5 | #5 of 69 | Oct 8, 2026 |
| Arena Agent | Arena | 0 ± 0 | #6 of 35 | Oct 12, 2026 |
| FrontierMath Tier 4 | Epoch AI | 87.8% ± 5.2% | #6 of 58 | Sep 1, 2026 |
| FrontierMath Tiers 1-3 | Epoch AI | 90.2% ± 1.8% | #4 of 71 | Sep 1, 2026 |
| OTIS Mock AIME 2024-2025 | Epoch AI | 100.0% ± 0.0% | #2 of 105 | Sep 1, 2026 |
| SimpleQA Verified | Epoch AI | 70.8% ± 1.4% | #6 of 68 | Sep 1, 2026 |
Arena (arena.ai), https://arena.ai/leaderboard
Epoch AI, ‘Capabilities & benchmarking’. Published online at epoch.ai. Retrieved from ‘https://epoch.ai/benchmarks’ [online resource].
List prices
| Platform | Input | Cached | Output | In effect | Source |
|---|---|---|---|---|---|
Claude APIclaude-fable-5-1 | $10.00 | $0.25 | $50.00 | Sep 1, 2026Current | Anthropic: Pricing (opens in a new tab) |
Amazon Bedrockanthropic.claude-fable-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) |
Google Vertex AIclaude-fable-5-1 | $10.00 | $0.25 | $50.00 | Sep 1, 2026Current · Global endpoint price; regional and multi-region endpoints cost more. | Google Cloud: Agent Platform pricing (opens in a new tab) |
Change history
ReleaseClaude Fable 5.1 releasedClaude API, Google Vertex AI3 breaks
Claude Fable 5.1 succeeds Claude Fable 5 at the same input and output prices, with cheaper cache reads. Google Cloud lists the same release date.
- Platform
- Claude API, Google Vertex AI
- Model
- Claude Fable 5.1
- ParametersForced tool choice (tool_choice "any" or "tool") returns a 400 error. Claude Fable 5 accepted it.
- BehaviorOnly Claude Fable 5.1 and Claude Mythos 5.1 read Claude Fable 5.1 thinking blocks, and only in the conversation that produced them.
- AvailabilityUnlike Claude Opus 5, it requires 30-day data retention and is not available under zero data retention unless Anthropic authorizes it.
Source: Anthropic, Claude Fable 5.1 (opens in a new tab); Anthropic, Claude Fable 5.1 and Claude Mythos 5.1 migration guide (opens in a new tab); Google Cloud, Claude Fable 5.1 on Google Cloud (opens in a new tab); Google Cloud, Gemini Enterprise Agent Platform release notes (opens in a new tab)
ReleaseClaude Fable 5.1 available on Amazon BedrockAmazon Bedrock
Bedrock added Claude Fable 5.1 as anthropic.claude-fable-5-1.
- Platform
- Amazon Bedrock
- Model
- Claude Fable 5.1
Source: Amazon Web Services, Amazon Bedrock ListFoundationModels, us-east-1 (opens in a new tab)