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.
—$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.
—$1.00OpenAI
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
—$6.00OpenAI
—$1,000OpenAI list price
Benchmarks
Gray Swan IPI · k = 1Prompt injection robustness — Attackers hide malicious instructions inside content the AI reads — a web page, an email, a document — and try to hijack what it does. Gray Swan's indirect prompt injection benchmark measures how often such an attack succeeds when the attacker gets a single try. Lower is better.
2.9%5.4%
Gray Swan IPI · k = 10Prompt injection robustness — Attackers hide malicious instructions inside content the AI reads — a web page, an email, a document — and try to hijack what it does. This variant gives the attacker 10 tries and counts an attack as successful if any of them works. Lower is better.
14.3%26%
Gray Swan IPI · k = 15Prompt injection robustness — Attackers hide malicious instructions inside content the AI reads — a web page, an email, a document — and try to hijack what it does. This variant gives the attacker 15 tries and counts an attack as successful if any of them works. Lower is better.
16.5%30.4%
SWE-Bench ProAgentic coding — Can the AI fix real bugs in real software? It's handed actual problems from open-source projects and has to write code that genuinely solves them. Higher is better.
55%63.4%
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%69.6%
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.
67.3%87.4%
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%83.9%
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better.
89.5%92.9%
MMMU-ProMultimodal reasoning — A tougher version of MMMU — college-level questions that mix images, diagrams, and text together. Higher is better.
80.4%80.7%
Overview
CompanyMetaOpenAI
Release dateApr 8 2026Jun 26 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

GPT-5.6 Terra leads Muse Spark on 6 of the 9 benchmarks they both report. Only GPT-5.6 Terra has a verified first-party price for an available API: $2.00 per million input tokens and $12.00 per million output tokens. No currently available pay-as-you-go API rate is tracked for Muse Spark. Muse Spark shipped 79 days before GPT-5.6 Terra, 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 Gray Swan IPI · k = 1, Muse Spark leads at 2.9% vs GPT-5.6 Terra at 5.4%. On Gray Swan IPI · k = 10, Muse Spark leads at 14.3% vs GPT-5.6 Terra at 26%. On Gray Swan IPI · k = 15, Muse Spark leads at 16.5% vs GPT-5.6 Terra at 30.4%. On SWE-Bench Pro, GPT-5.6 Terra leads at 63.4% vs Muse Spark at 55%. On DeepSWE 1.1, GPT-5.6 Terra leads at 69.6% vs Muse Spark at 10%. On Terminal-Bench 2.1, GPT-5.6 Terra leads at 87.4% vs Muse Spark at 67.3%. On ARC-AGI-2, GPT-5.6 Terra leads at 83.9% vs Muse Spark at 42.5%. On GPQA Diamond, GPT-5.6 Terra leads at 92.9% vs Muse Spark at 89.5%. On MMMU-Pro, GPT-5.6 Terra leads at 80.7% vs Muse Spark at 80.4%.