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.
1M400k
API pricingUSD per 1M tokens · lower wins
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.
$1.25Meta—
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$4.25Meta—
$463Meta—
Benchmarks
BullshitBench v2Nonsense detection — Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better.
50%39%
Overview
CompanyMetaOpenAI
Release dateAug 5 2026Sep 15 2025
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Muse Spark 1.2 leads GPT-5-Codex on 1 of the 1 benchmark they both report (BullshitBench v2). GPT-5-Codex shipped 324 days before Muse Spark 1.2, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Muse Spark 1.2) vs 400k (GPT-5-Codex).

On BullshitBench v2, Muse Spark 1.2 leads at 50% vs GPT-5-Codex at 39%.