Google: Gemini 3.1 Pro Preview

google/gemini-3.1-pro-preview · GoogleNot yet established

Declared family: Gemini
Evidence confidence: Unknown
Declared tokenizer tag: Gemini
Entered catalogue: 19 February 2026
Last tested: Not yet measured
Measurement: Awaiting measurement

Evidence stack

Signals of different kinds, weighed together

Signal	Result	Reference
Tokenizer signature	Not measured	–
API surface	Identical contract to 2 other entries	api_16435537
Context and output	1,048,576 context · 65,536 max output	declared
Reasoning contract	Mandatory · efforts high, medium, low · default medium	declared
Serving providers observed	None recorded yet	–

Declared record

What the catalogue claims about this model

Gemini 3.1 Pro Preview is Google’s frontier reasoning model, delivering enhanced software engineering performance, improved agentic reliability, and more efficient token usage across complex workflows. Building on the multimodal foundation...

Modalities: text+image+file+audio+video->text
Declared tokenizer: Gemini
Prompt price: $2.00 / M tokens
Completion price: $12.0 / M tokens

Supported parameters

include_reasoningmax_tokensreasoningreasoning_effortresponse_formatseedstopstructured_outputstemperaturetool_choicetoolstop_p

defaults: {"temperature":null,"top_p":null,"top_k":null,"frequency_penalty":null,"presence_penalty":null,"repetition_penalty":null}

Catalogue entry

History

Every observation, kept as taken

19 February 2026Enters the OpenRouter catalogue declared as Gemini.

Cite this page as the evidence record for Google: Gemini 3.1 Pro Preview: 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.