GPT-5.6 Luna 80% cheaper: what it means for GitHub Copilot users

Do you have a GitHub Copilot licence, and have your credits been melting faster than ever for a month or two now? Same problem here.

Back before usage-based billing, it was all so simple. There was a rivalry between Anthropic (Claude) and OpenAI (Codex), but as GitHub Copilot users we mostly watched usage-limit resets pass us by.

But wonders never cease. On July 30, 2026, OpenAI cut the API price of GPT-5.6 Luna by a full 80%, and GPT-5.6 Terra by 20%.¹ I expected a catch somewhere, but no: the change is visible inside GitHub Copilot itself too.

// GPT-5.6 price cut, July 30 2026

Luna (light, fast)−80%

Terra (balanced)−20%

Sol (flagship)unchanged

GPT-5.6 with thinking effort set to high (the default is medium) has since become my new go-to inside GitHub Copilot. Thanks to the price cut, I can do this without it taking a real toll on my credits.

Model picker in GitHub Copilot with GPT-5.6 Luna selected, showing credit usage per 1M tokens

The model picker in GitHub Copilot, showing GPT-5.6 Luna's credit usage after the price cut.

To quote the great philosopher Krusty The Clown: it's not just good, it's good enough.

// Source

OpenAI — Advancing the price-performance frontier with GPT-5.6

Fly me to the moon: GPT-5.6 Luna is 80% cheaper

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Model behavior: Microsoft 365 Copilot Basic alongside GitHub Copilot