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Claude Fable 5
anthropicanthropic/claude-fable-5
How TheRouter serves this differently from the vendor
As the vendor operates it
Anthropic operates Fable 5 natively through Claude API semantics, including adaptive thinking, refusal handling, and provider-specific deployments such as Bedrock, Vertex AI, Microsoft Foundry, and Snowflake Cortex.
On TheRouter
TheRouter serves it as the catalog model id anthropic/claude-fable-5 on the OpenAI-compatible chat completions path; operational pricing, limits, and supported parameters are taken from the live TheRouter catalog, not copied into this page.
API guide
Chat completion
Use the OpenAI-compatible chat completions endpoint when you want TheRouter to route Claude Fable 5 through its configured provider chain.
cURL
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"anthropic/claude-fable-5","messages":[{"role":"user","content":"Hello"}]}'Tool calling
Fable 5 is most useful when the router preserves tool calls and fallback semantics for long-running agents.
cURL
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"anthropic/claude-fable-5","messages":[{"role":"user","content":"Summarize the deployment plan"}],"tools":[{"type":"function","function":{"name":"record_decision","description":"Record a routing decision","parameters":{"type":"object","properties":{"decision":{"type":"string"}},"required":["decision"]}}}]}'Related news
- NewsClaude Fable 5 Is Back — But With Nationality Controls, Stronger Classifiers, and a Credit Pricing Cliff Tomorrow
- NewsClaude Fable 5's New Tokenizer Inflates Token Counts 30%: What Every Operator Must Audit Before Migrating
- NewsClaude Fable 5 Server-Side Fallback API: Handle Refusals Without a Retry Loop
- NewsClaude Fable 5 Is Live: What the New Model ID, Refusal Semantics, and Token Accounting Mean for Your Routing Layer
- NewsClaude Fable 5 Lands on Snowflake Cortex AI: What the New Inference Endpoint Means for Your Routing Architecture
Guides
Fact ledger — every claim on this page traces here
| source | URL | retrieved | |
|---|---|---|---|
| Release date | platform.claude.com ↗ | 2026-07-30 | verified |
| Anthropic model id | platform.claude.com ↗ | 2026-07-30 | verified |
| Context window | — | — | verified |
| Maximum output | — | — | verified |
| Training cutoff | — | — | unknown |
| Deployment | www.snowflake.com ↗ | 2026-07-30 | verified |
| License | www.anthropic.com ↗ | 2026-07-30 | verified |
| Official benchmark table | platform.claude.com ↗ | 2026-07-30 | unknown |
| TheRouter live snippet verification | therouter.ai ↗ | 2026-07-30 | unknown |
| Independent benchmark table | www.anthropic.com ↗ | 2026-07-30 | unknown |
| Claude Fable 5 returns with nationality controls and a credit pricing cliff | therouter.ai/news ↗ | 2026-07-30 | verified |
| Is Claude Fable 5 a good default model? | platform.claude.com ↗ | 2026-07-30 | to verify |
| What should a router log for Fable 5 traffic? | therouter.ai ↗ | 2026-07-30 | to verify |