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OpenAI · Language model

GPT-5.2

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

GPT-5.2 is the latest frontier-grade model in the GPT-5 series, offering stronger agentic and long context perfomance compared to GPT-5.1. It uses adaptive reasoning to allocate computation dynamically, responding quickly...

Specifications

Context window
400,000 tokens
Max output
128,000 tokens
Input
file, image, text
Output
text
Reasoning effort
xhigh, high, medium, low, none
Tokenizer
GPT
Moderation
provider-moderated

Supported parameters

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

  • max_completion_tokens
  • max_tokens
  • reasoning
  • reasoning_effort
  • 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","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'