Compare AI models

Specifications
Context windowHow much information the model can work with in one request, measured in tokens — pieces of words or other data. This includes your question, attachments, conversation and reply. Limits can vary by model variant and provider.
—1.05M
API pricingUSD per 1M tokens · lower wins · base tier
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it.
—$0.10
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one.
—$0.50
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again.
—$0.01
Cheapest inputLowest input rate across every provider on OpenRouter, the lab included. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page.
—$0.05OpenAI
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
—$0.25OpenAI
—$45.00OpenAI list price
Benchmarks
DeepSWE 1.1Agentic coding — Artificial Analysis' independent test of deep, agentic software-engineering work — the AI has to plan and carry out substantial coding tasks end to end. (Version 1.1 of the test.) Higher is better.
10%66.6%
ARC-AGI-2Abstract reasoning — Puzzle-style tests of abstract reasoning and pattern-finding — the kind of thing people find easy but AIs often struggle with. Higher is better.
42.5%59.3%
Overview
CompanyMetaOpenAI
Release dateApr 8 2026Sep 22 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

GPT-6 Luna leads Muse Spark on 2 of the 2 benchmarks they both report (DeepSWE 1.1, ARC-AGI-2). Only GPT-6 Luna has a verified first-party price for an available API: $0.10 per million input tokens and $0.50 per million output tokens. No currently available pay-as-you-go API rate is tracked for Muse Spark. Muse Spark shipped 167 days before GPT-6 Luna, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

On DeepSWE 1.1, GPT-6 Luna leads at 66.6% vs Muse Spark at 10%. On ARC-AGI-2, GPT-6 Luna leads at 59.3% vs Muse Spark at 42.5%.