Anthropic: Claude Fable 5 (batch)

anthropic/claude-fable-5:batch · AnthropicNot yet established

Tokenizer lineage (measured): Claude
Declared tokenizer tag: Claude
Entered catalogue: 9 June 2026
Measurement: Variant: inherits its base model’s measurement
Evidence confidence: Moderate

Why moderate: inherited from anthropic/claude-fable-5: a serving variant shares its base model's tokenizer.

Evidence

✓ inherited from anthropic/claude-fable-5: a serving variant shares its base model's tokenizer

Compare with Anthropic: Claude Fable 5

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This entry is a serving variant of Anthropic: Claude Fable 5. A variant shares its base model's tokenizer by construction, so the measurement lives on the base record and this page inherits it.

Identity statement

Anthropic: Claude Fable 5 (batch) is Anthropic's model. Its measured tokenizer sits with the Claude group, which is evidence that it builds on the Claude tokenizer. Tokenizer reuse is normal engineering, open vocabularies travel between labs, and this says nothing against Anthropic's authorship of the model itself.

What we checked

Four different kinds of evidence, and what each one showed

We checked	What we found	Where it came from
How it counts tokens	Not measured yet	we measured it
How its API is set up	A combination of settings no other listing in the catalogue uses	api_21c18cd3
How much it can read and write	Reads up to 1,000,000 tokens at once, writes up to 128,000	its own listing
Whether it thinks before answering	Always reasons, and cannot be turned off, at max, xhigh, high, medium, low, high by default	its own listing

Declared record

What the catalogue claims about this model

Claude Fable 5 is a Mythos-class model from Anthropic, built for autonomous knowledge work and coding. It supports text, image, and file inputs with text output, with reasoning support and...

Modalities: text+image+file->text
Declared tokenizer: Claude
Prompt price: $5.00 / M tokens
Completion price: $25.0 / M tokens

Supported parameters

include_reasoningmax_tokensreasoningreasoning_effortresponse_formatstopstructured_outputstool_choicetoolsverbosity

Default settings

Temperature: Unspecified
Top p: Unspecified
Top k: Unspecified
Frequency penalty: Unspecified
Presence penalty: Unspecified
Repetition penalty: Unspecified

Catalogue entry

History

Every observation, kept as taken

9 June 2026Enters the OpenRouter catalogue declared as Claude.