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OpenAI · Language model

GPT-5.4 Pro

openai/gpt-5.4-pro
  • Language
Released Mar 5, 2026

GPT-5.4 Pro is OpenAI's most advanced model, building on GPT-5.4's unified architecture with enhanced reasoning capabilities for complex, high-stakes tasks. It features a 1M+ token context window (922K input, 128K...

Specifications

Context window
1,050,000 tokens
Max output
128,000 tokens
Input
text, image, file
Output
text
Reasoning effort
xhigh, high, medium (always on)
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-5.4-pro","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'