OpenAI: o3 Pro
openai/o3-pro · OpenAINot yet established- Declared family
- GPT
- Evidence confidence
- Unknown
- Declared tokenizer tag
- GPT
- Entered catalogue
- 10 June 2025
- Last tested
- Not yet measured
- Measurement
- Awaiting measurement
| Signal | Result | Reference |
|---|---|---|
| Tokenizer signature | Not measured | – |
| API surface | Identical contract to 1 other entry | api_4347be44 |
| Context and output | 200,000 context · 100,000 max output | declared |
| Reasoning contract | Optional | declared |
| Serving providers observed | None recorded yet | – |
The o-series of models are trained with reinforcement learning to think before they answer and perform complex reasoning. The o3-pro model uses more compute to think harder and provide consistently...
Supported parameters
include_reasoningmax_tokensreasoningresponse_formatseedstructured_outputstool_choicetools
defaults: {"temperature":null,"top_p":null,"frequency_penalty":null}
Cite this page as the evidence record for OpenAI: o3 Pro: 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.