IBM: Granite 4.1 8B is IBM's model. Its measured tokenizer sits with the OpenAI cl100k group, which is evidence that it builds on the OpenAI cl100k tokenizer. Tokenizer reuse is normal engineering, open vocabularies travel between labs, and this says nothing against IBM's authorship of the model itself.
cl100k_base is an open vocabulary table anyone can build on. Sharing it says which dictionary the model reads with, and nothing about who made the model.
Granite 4.1's endpoint counts match OpenAI's open cl100k_base encoding on all 50 strings, the same result as Granite 4.0 and Microsoft's Phi-4. The three share one signature group because both labs adopted the tokenizer OpenAI released as open source with tiktoken.
| Signal | Result | Reference |
|---|---|---|
| Tokenizer signature | Exact match with 2 other models | tk_ba918336 |
| API surface | No other entry shares this exact contract | api_e2900825 |
| Context and output | 131,072 context · 131,072 max output | declared |
| Reasoning contract | None declared | declared |
| Serving providers observed | CoreWeave | measured 21 August 2026 |
Click a row to open the full comparison.
An x marks a row excluded as corrupt (caching or provider interference detected during measurement). Overhead subtracted: 8 prompt tokens.
Granite 4.1 8B is a dense, decoder-only 8-billion-parameter language model from IBM, part of the Granite 4.1 family. It supports a 131K-token context window and is designed for enterprise tasks...
Supported parameters
frequency_penaltylogprobsmax_tokenspresence_penaltyrepetition_penaltyresponse_formatseedstopstructured_outputstemperaturetool_choicetoolstop_ktop_logprobstop_p
defaults: {"temperature":null,"top_p":null,"top_k":null,"frequency_penalty":null,"presence_penalty":null,"repetition_penalty":null}
Cite this page as the evidence record for IBM: Granite 4.1 8B: the URL is stable, measurements are dated, and revisions append to the history above. Method: tokenizer fingerprinting, v1, 50 strings. The raw data behind every figure is on the data page.
