AI Desk · AI FingerprintingNew arrival
Why high: an exact fingerprint shared with 5 models that declare the same family, without a second signal of a different kind yet.
Meta: Muse Spark Open is Meta's model. Its measured tokenizer sits with the Llama4 group, which is evidence that it builds on the Llama4 tokenizer. Tokenizer reuse is normal engineering, open vocabularies travel between labs, and this says nothing against Meta's authorship of the model itself.
| We checked | What we found | Where it came from |
|---|---|---|
| How it counts tokens | Counts every one of the 50 test strings exactly like 5 other models | tk_20b9d005 |
| How its API is set up | A combination of settings no other listing in the catalogue uses | api_9809b754 |
| How much it can read and write | Reads up to 1,048,576 tokens at onceOpenRouter's listing shows 943,718 output tokens, which is 90% of the context window, the figure it carries where the provider declares no maximum. | its own listing |
| Whether it thinks before answering | Always reasons, and cannot be turned off, at xhigh, high, medium, low, medium by default | its own listing |
| Who served our requests | BaseTen | we measured it, 17 October 2026 |
Click a row to open the full comparison.
We sent Meta: Muse Spark Open fifty short pieces of text and recorded what each one cost it in tokens. The bars below are those costs. Two models built on the same tokenizer produce the same bars; a model built on a different one produces a different set, which is what makes this a fingerprint.
Overhead subtracted: 145 prompt tokens.
Muse Spark Open is a coding-optimized open-weight model. Trained specifically for agentic coding workflows, it delivers higher first-attempt accuracy, reliable tool calling, and deep codebase understanding across the repos developers...
Supported parameters
frequency_penaltyinclude_reasoninglogit_biaslogprobsmax_tokensmin_ppresence_penaltyreasoningreasoning_effortrepetition_penaltyresponse_formatseedstopstructured_outputstemperaturetool_choicetoolstop_ktop_logprobstop_p
