GPT 5.6 Luna

openai/gpt-5.6-luna

A chat model with a 1.1M-token context window, at $0.21 per million input tokens and $1.26 per million output tokens.

Details

Maker: openai
Kind: Chat
Context window: 1,050,000 tokens
Max output: 128,000 tokens
Input: $0.21 per million tokens
Cached input: $0.021 per million tokens, 90% off
Cache write: $0.2625 per million tokens
Output: $1.26 per million tokens
Capabilities: Reasoning, tool use, vision, file input, web search, fast
Takes: Text, image, pdf
Returns: Text
Zero data retention: Not on every provider
No training on requests: Yes, on every provider
Released: 2026-07-09
Newer model: openai/gpt-6-lunaReleased later by the same maker, costs no more, and lists the same capabilities. Compare the two

Description

GPT-5.6 Luna is a fast, affordable GPT-5.6 model that brings strong capability at the lowest cost in the series.

Call it

curl

curl https://phantom.codes/v1/chat/completions \
  -H "Authorization: Bearer $PHANTOM_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5.6-luna",
    "messages": [
      {"role": "user", "content": "Hello"}
    ]
  }'

Set PHANTOM_KEY to your key. Any OpenAI client works with the base URL https://phantom.codes/v1.

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