ChatGPT is OpenAI's consumer and business AI product, powered by the GPT model family. GPT-5.6 is the current generation for advanced reasoning, coding, computer use, and professional work.
ChatGPT launched in November 2022 on GPT-3.5 and later added GPT-4, GPT-4o, the o-series reasoning models, and GPT-5. OpenAI released GPT-5.6 in July 2026 across ChatGPT, Codex, and the API. The generation includes the flagship Sol tier, the balanced Terra tier, and the fast, cost-efficient Luna tier. GPT-5.5 Instant remains available for fast everyday conversations, while GPT-5.6 powers higher-effort reasoning options on eligible plans.
Further reading
Muse is Meta's new proprietary multimodal reasoning and agent family. Muse Spark 1.1 powers Meta AI and succeeds Llama as Meta's actively promoted assistant model line.
Meta introduced Muse Spark in April 2026 as the first model from Meta Superintelligence Labs' ground-up Muse series. It is a natively multimodal reasoning model with tool use, visual reasoning, and multi-agent orchestration. Muse Spark 1.1, announced in July 2026, adds planning and action capabilities across research, productivity, and connected applications. It powers Meta AI and is available through Meta's products, with API access offered in private preview rather than as open weights.
Further reading
ChatGPT