First-party API ID
claude-fable-5-1
Use the exact ID and verify it in the live Models API before production routing.
Anthropic model record · checked September 2, 2026
Answer first
Fable 5.1 is the current broadly available Fable generation.
Use claude-fable-5-1 on the first-party API. Evaluate public token and cache pricing, safeguard redirects, effort defaults, cloud entitlement, and Enterprise Frontier Safeguards on the exact product and account.
Verified provider facts
General availability
Anthropic + 3 clouds
Anthropic lists its products, AWS, Google Cloud, and Microsoft Azure; each cloud keeps its own IDs, regions, quotas, and contract.
Public token price
$10 in · $50 out
Per million tokens where usage is token-billed. Cache reads are separately priced at $0.25 per million tokens.
Safeguard profile
Broad access
The same base model as Mythos 5.1, with safeguards designed for general availability.
Choose by deployment contract
Starting a new API integration?
Evaluate claude-fable-5-1 first. Keep claude-fable-5 only when compatibility tests, an existing dependency, or a contract requires the previous generation.
Comparing price with Fable 5?
Measure the real cache-read share. Anthropic estimates about 25% lower typical cost and up to about 45% for cache-heavy agentic work, but the result depends on the workload.
Handling security or life-sciences work?
Test permitted work and redirects. Vulnerability discovery is allowed, while exploit generation, penetration testing, binary scanning, and professional life-sciences work can route to Opus models.
Need enterprise privacy controls?
Verify transition zero data retention or phased Enterprise Frontier Safeguards eligibility, storage, keys, review ownership, cloud cost, and supported surface.
Claude Code defaults Fable 5.1 to High effort, while Claude Cowork and Claude.ai default to Medium according to the launch announcement. Record the chosen effort rather than comparing products under different defaults. Preserve the Fable 5 record for regression tests and use the Fable versus Mythos lifecycle guide for the safeguard decision.
Source and availability boundaries
Official 5.1 launch
Shared-model relationship, general and trusted access, API ID, public pricing, safeguards, effort defaults, clouds, and watermark program.
Enterprise Frontier Safeguards
Phased rollout, transition ZDR, customer-controlled storage, keys, automated monitoring, review ownership, surfaces, and cloud cost.
Provider benchmarks and savings estimates are not independent guarantees. This page does not infer a context window, output limit, plan inclusion, cloud region, Mythos entitlement, or Flowith availability from the launch announcement.
Continue by decision
Claude Fable 5.1 questions
Claude Fable 5.1 is Anthropic's current generally available Fable generation, released September 1, 2026. Anthropic says it uses the same underlying model as Mythos 5.1 but applies a safeguard profile intended for broad access.
The first-party Claude API model ID is claude-fable-5-1. AWS, Google Cloud, and Microsoft Azure can use different catalog names, endpoints, regions, and entitlement rules.
Anthropic lists $10 per million input tokens and $50 per million output tokens, plus $0.25 per million cache-read tokens where usage is token-billed. Recheck cache creation, tools, effort, cloud markup, and the live price before budgeting.
Anthropic describes the same base model with different safeguard and access profiles. Fable 5.1 is generally available; Mythos 5.1 is restricted to vetted cybersecurity and life-sciences programs.
Do not assume it universally. Anthropic says eligible Fable 5 and Fable 5.1 customers can use zero data retention until Enterprise Frontier Safeguards is ready. Confirm eligibility, rollout phase, surface, storage, review, and contract.
This page does not claim a Flowith mapping or entitlement. Anthropic and cloud availability are separate from the live Flowith model selector, plan, routing, limits, pricing, and data handling.