AI Desk · AI Fingerprinting · Compare
Anthropic: Claude 3 Haiku · Anthropic: Claude Fable 5.1
Identity similarity: lowDivergent fingerprints · 15/49These models tokenise differently. The rows that part here are the English prose, whitespace, digit, CJK, emoji and non-Latin script strings. Divergence on high-information strings separates unrelated vocabularies within a handful of samples.
Anthropic: Claude 3 Haiku recordAnthropic: Claude Fable 5.1 recordOpen in the interactive bench
Tokenizer fingerprint
15 of 49 mutually clean strings agree| Test string | Anthropic: Claude 3 Haiku | Anthropic: Claude Fable 5.1 | Verdict |
|---|---|---|---|
| en-prose | 15 | 24 | differs |
| en-long | 17 | 28 | differs |
| spaces-20 | 4 | 4 | match |
| spaces-60 | 6 | 6 | match |
| tabs-20 | 4 | 4 | match |
| newlines-20 | 3 | 4 | differs |
| mixed-ws | 9 | 9 | match |
| digits-9 | 4 | 3 | differs |
| digits-12 | 5 | 4 | differs |
| digits-30 | 11 | 10 | differs |
| digits-sep | 8 | 7 | differs |
| float-long | 10 | 9 | differs |
| zh-common | 19 | 18 | differs |
| zh-long | 25 | 24 | differs |
| zh-rare | 21 | 20 | differs |
| ja-kana | 12 | 12 | match |
| ja-kanji | 17 | 16 | differs |
| ko | 20 | 19 | differs |
| ru | 14 | 14 | match |
| ar | 21 | 21 | match |
| he | 18 | 18 | match |
| hi | 23 | 23 | match |
| th | 25 | 25 | match |
| el | 22 | 22 | match |
| emoji-basic | 11 | 10 | differs |
| emoji-skin | 26 | 25 | differs |
| emoji-zwj-family | 15 | 14 | differs |
| emoji-zwj-x3 | 43 | 42 | differs |
| emoji-flags | 25 | 24 | differs |
| emoji-prof | 28 | 27 | differs |
| math | 47 | 46 | differs |
| boxdraw | 29 | 28 | differs |
| combining | 6 | 6 | match |
| cjk-ext-b | 17 | 16 | differs |
| surrogates | 55 | 54 | differs |
| zalgo | 36 | 36 | match |
| rtl-mix | 10 | 11 | differs |
| py-code | 30 | 30 | match |
| py-indent | 19 | 19 | match |
| json | 23 | 29 | differs |
| html | 17 | 18 | differs |
| regex | 52 | 63 | differs |
| camel | 7 | 16 | differs |
| snake | 11 | 14 | differs |
| rare-word-x5 | 41 | 55 | differs |
| repeat-tok | 21 | 60 | differs |
| base64 | 43 | x | – |
| hex | 14 | 18 | differs |
| url | 22 | 26 | differs |
| uuid | 28 | 27 | differs |
Values are the marginal prompt-token cost of each string with the model's fixed overhead subtracted. An x marks a row excluded as corrupt for that model.
API surface
The declared serving contracts differ| Field | Anthropic: Claude 3 Haiku | Anthropic: Claude Fable 5.1 | Verdict |
|---|---|---|---|
| Context length | 200000 | 1000000 | × differs |
| Max output tokens | 4096 | 128000 | × differs |
| Supported parameters | max_tokens, stop, temperature, tool_choice, tools, top_k, top_p | include_reasoning, max_completion_tokens, max_tokens, reasoning, reasoning_effort, response_format, stop, structured_outputs, tool_choice, tools, verbosity | × differs |
| Defaults | {} | {} | ✓ match |
| Reasoning contract | – | {"mandatory":true,"supported_efforts":["max","xhigh","high","medium","low"],"default_effort":"high"} | × differs |
| Modalities | text+image->text | text+image+file->text | × differs |
Method: tokenizer fingerprinting, v1, 50 strings. This page is static and dated; the interactive bench compares any two of the 337 measured models.