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OpenAI · Language model

GPT-5.2 Chat

openai/gpt-5.2-chat
  • Language
Released Dec 10, 2025

GPT-5.2 Chat (AKA Instant) is the fast, lightweight member of the 5.2 family, optimized for low-latency chat while retaining strong general intelligence. It uses adaptive reasoning to selectively “think” on...

Specifications

Context window
128,000 tokens
Max output
32,000 tokens
Input
file, image, text
Output
text
Tokenizer
GPT

Supported parameters

Accepted by the model and forwarded as-is by the gateway.

  • max_completion_tokens
  • response_format
  • seed
  • structured_outputs
  • tool_choice
  • tools

Use it

POST /api/v1/chat/completions · MCP chat · full reference

curl https://omnirail.org/api/v1/chat/completions \
  -H "Authorization: Bearer $OMNIRAIL_KEY" -H "Content-Type: application/json" \
  -d '{"model":"openai/gpt-5.2-chat","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'