Compare AI models

Specifications
Context windowHow much text the model can hold in mind at once — your question, any documents you attach, the conversation so far, and its own reply. Go past it and the earliest part falls out of view.
1M—
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.
—$2.00
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.
—$12.00
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.
—$0.20
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$1.00OpenAI
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$4.25Meta$6.00OpenAI
$463Meta$1,000OpenAI list price
Benchmarks
CursorBench 4.0Agentic coding — Cursor's own test of coding agents on ambiguous, multi-file tasks taken from real Cursor sessions — editing, refactoring, investigating a codebase, understanding what the user meant, managing jobs and following a design. Cursor runs each model at several reasoning efforts; each release here carries the score of its best listed effort. Scores aren't comparable with earlier CursorBench versions. Higher is better.
41.6%41.3%
Terminal-Bench 4.0Agentic terminal coding — Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? Version 4.0 recalibrated how much time, CPU and memory each task gets, removed eight tasks and fixed nineteen, so fewer runs fail for reasons that have nothing to do with the model. Scores are not comparable with earlier versions. Higher is better.
14.55%21.52%
Terminal-Bench 2.1Agentic terminal coding — Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? Higher is better.
88.8%84.3%
threejsevalCommunity preference (Three.js) — Every model gets the same prompt — "the Eiffel Tower", "a glass fishbowl", "a robot arm picking toys into a box" — and builds a 3D scene in Three.js. Real people then see two scenes side by side, names hidden, and vote for the one they prefer. The votes become a chess-style Elo rating on threejseval.com, averaged across all the prompts. It measures whether the scene looks and moves right to a human eye, not whether the code passes a test. Higher is better.
14501449
Overview
CompanyMetaOpenAI
Release dateSep 2 2026Jun 26 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Muse Spark 1.3 leads GPT-5.6 Terra on 3 of the 4 benchmarks they both report (CursorBench 4.0, Terminal-Bench 4.0, Terminal-Bench 2.1, threejseval). Only GPT-5.6 Terra has a verified first-party API price: $2.00 per million input tokens and $12.00 per million output tokens. No pay-as-you-go API rate is tracked for Muse Spark 1.3. GPT-5.6 Terra shipped 68 days before Muse Spark 1.3, 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 CursorBench 4.0, Muse Spark 1.3 leads at 41.6% vs GPT-5.6 Terra at 41.3%. On Terminal-Bench 4.0, GPT-5.6 Terra leads at 21.52% vs Muse Spark 1.3 at 14.55%. On Terminal-Bench 2.1, Muse Spark 1.3 leads at 88.8% vs GPT-5.6 Terra at 84.3%. On threejseval, Muse Spark 1.3 leads at 1450 vs GPT-5.6 Terra at 1449.