Why high: an exact fingerprint shared with 4 models.
MoonshotAI: Kimi K2 Thinking is Moonshot AI's model, and its measured tokenizer sits in Moonshot AI's own signature group alongside its sibling models. Measured models from Fireworks carry the same vocabulary, which reads as reuse of Moonshot AI's tokenizer line and questions nobody's authorship; they are listed under "Shares this fingerprint" below.
| We checked | What we found | Where it came from |
|---|---|---|
| How it counts tokens | Counts every one of the 50 test strings exactly like 4 other models | tk_ea6068bf |
| How its API is set up | A combination of settings no other listing in the catalogue uses | api_de12197a |
| How much it can read and write | Reads up to 262,144 tokens at onceOpenRouter's listing shows 235,929 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 | its own listing |
| Who served our requests | we measured it, 3 September 2026 |
Click a row to open the full comparison.
We sent MoonshotAI: Kimi K2 Thinking 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: 7 prompt tokens.
Kimi K2 Thinking is Moonshot AI’s most advanced open reasoning model to date, extending the K2 series into agentic, long-horizon reasoning. Built on the trillion-parameter Mixture-of-Experts (MoE) architecture introduced in...
Supported parameters
frequency_penaltyinclude_reasoninglogprobsmax_tokenspresence_penaltyreasoningrepetition_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}
