GPT-5.6 Luna (Reasoning)

by OpenAI

GPT-5.6 Luna (Reasoning) is a reasoning model from OpenAI, released on July 9, 2026. It has a 1.1M-token context window and can generate up to 128K output tokens. API pricing is $0.2 per 1M input tokens and $1.2 per 1M output tokens.

GPT-5.6 Luna is the fastest and most cost-efficient tier of OpenAI's GPT-5.6 family, designed for cost-sensitive, high-volume workloads. It brings strong capability at OpenAI's lowest GPT-5.6 price, supports max reasoning effort, and has a 1.05M-token context window.

Key specs

ProviderOpenAI
Release date2026-07-09
Licenseproprietary
Context window1.1M tokens
Max output128K tokens
Input price$0.2 / 1M tokens
Output price$1.2 / 1M tokens
Intelligence Score44.3
Coding index34.7
Output speed253 tokens/s
Time to first token2.25 s

Quick answers

What is the context window of GPT-5.6 Luna (Reasoning)?

GPT-5.6 Luna (Reasoning) has a context window of 1.1M tokens, with a maximum output of 128K tokens per response.

How much does GPT-5.6 Luna (Reasoning) cost?

GPT-5.6 Luna (Reasoning) costs $0.2 per 1M input tokens and $1.2 per 1M output tokens through the API.

Is GPT-5.6 Luna (Reasoning) open source?

No. GPT-5.6 Luna (Reasoning) is a proprietary model from OpenAI (proprietary license).

When was GPT-5.6 Luna (Reasoning) released?

OpenAI released GPT-5.6 Luna (Reasoning) on July 9, 2026.

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