Primary source AIArticle·23 September 2026·7 min read

GPT-6 Sol and Luna: OpenAI Cuts API Prices in Half

After Astra, OpenAI rounds out its new generation with two cheaper models and takes direct aim at Claude on the cost/intelligence ratio.

ShareWhatsApp X LinkedIn Facebook

Save to my selection

GPT-6 Sol and Luna: OpenAI Cuts API Prices in Half

Source : OpenAI · OpenAIView original ↗

Who covers it

Techmeme leadHacker News 1388 pts ↗

Picked up by 32 outlets · 1 top-tier · 11 tech · 3 forums · 28 social posts

In brief

OpenAI completes the GPT-6 family with Sol and Luna, two models trained using the same methods as Astra but optimized for cost, with API prices cut 50% compared to GPT-5.6's promotional rate. The announcement is packed with numerical comparisons against Claude Opus 5 and Fable 5.1, where Sol matches or beats scores for 80 to 90% less per task. On top of that comes heavy work on prompt caching for agents and immediate availability in ChatGPT Work, Codex, and the API.

🍺 Bar-stool version

You know the drill: the flagship model launches first to impress everyone, and the affordable versions show up three weeks later to collect the cash. Sol and Luna are the GPT-6 models that cost half as much and, on OpenAI's own benchmarks, beat Claude Opus 5 at 9% of its price — a figure delivered with the calm of a salesman telling you the deal ends tonight. That's the real story: for agents running in loops for hours, the bill matters just as much as the intelligence. When an OpenAI researcher burns $600 worth of tokens a day on median, you understand why price suddenly became a product feature.

Key takeaways

1
OpenAI expands the GPT-6 family with Sol and Luna, trained with methods similar to Astra's but positioned around cost efficiency.
2
API prices drop 50% compared to GPT-5.6's promotional rate: Sol falls to $2 / $10 per million tokens (input/output), Luna to $0.10 / $0.50.
3
On AutomationBench 1.0.6, Sol at xhigh effort scores 33.2% for $0.27 per task, versus 26.9% for Claude Opus 5 at max effort — 11.1 times more expensive.
4
On DeepSWE v1.1, Sol at max hits 68.8%, just 1.1 points behind Claude Fable 5's best score in the evaluation, at about 80% lower cost per task.
5
Factual reliability improves: Sol makes roughly half as many errors as its predecessor on the internal evaluation built from real flagged user conversations.
6
Prompt caching gets reworked: better default hit rates, 90% discount on cached input tokens, a dashboard and diagnostic tool, and effort or tool changes that no longer break the cache.
7
Available today in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise, and Edu; Luna also comes to Free and Go accounts in the desktop app, and the API exposes gpt-6-sol and gpt-6-luna.

A Three-Tier Family

In OpenAI's messaging, Astra remains the pinnacle: the smartest, most aligned model, the one you pick when you want zero compromise.

The War of Cost Per Task

The price cut is significant: $2 for input and $10 for output per million tokens for Sol, $0.10 and $0.50 for Luna — half the promotional rate of the corresponding GPT-5.6 models.

Code, Factuality, Computer Use

On code, OpenAI justifies its logic with its own internal numbers: valued at API prices, daily token consumption exceeds $600 for the median researcher and $7,000 at the 90th percentile.

Caching, the Agents' Quiet Weapon

The least flashy part of the post may be the most structurally important.

Style, Alignment, and Availability

OpenAI also carried Astra's communication style over to Sol and Luna: more clarity, less jargon, fewer strange turns of phrase, less low-value detail, and slightly shorter responses.

Why it matters

This announcement says less about the state of the art than about the state of the market.

Older than 30 days: the archive

This article is more than 30 days old

A free account opens articles from the last 30 days in full. The full archive is in the Pro plan.

Create my account

Already a member? Log in

Compare plans →

#openai #gpt-6 #llm #api #agents #cost

Original source

Introducing GPT-6 Sol and Luna

OpenAI

Open the article ↗

For you

Put it to work on your sources.

Free: a month of articles and three sources of your own. Pro: the whole archive and your sources, from €8/month.

Create my account →

For your team

The same machine, on your topics.

A space in your colours, your watch angles, your curators. Pilot open to three companies.

Request pilot access →