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
Official counting docs →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.