Anthropic Claude · API counting required
Claude Fable 5 Token Counter
Claude Fable 5 uses Anthropic's newer tokenizer. For an accurate count, use the Messages token counting endpoint with the exact model and request structure.
Accuracy note
Reference page. The local explorer is not Claude's tokenizer. Anthropic's count_tokens endpoint is the authoritative method for Claude requests.
Frequently asked questions
How do I count Claude Fable 5 tokens?
Use Anthropic's Messages token counting endpoint and pass Claude Fable 5 as the model.
Did Claude Fable 5 change tokenizers?
Yes. Anthropic documents that Fable 5 uses the newer tokenizer introduced with Claude Opus 4.7.
Is the token counting endpoint billed?
Anthropic currently documents token counting as free, subject to rate limits; check the official documentation for changes.