Meta Watermelon Release Date: What Meta Launched on 12 October

Meta released a new family of frontier models, Muse Wonder and Muse Wonder Full, on Monday 12 October 2026, and as of 16 October 2026 none of Meta's own announcement pages uses the codename Watermelon in its text. On versus, the prediction Will Meta release its Watermelon AI model by 31 Oct? has shown as settled since 10:07 UK time on 13 October 2026, so no price is quoted here.

This guide, for readers in Great Britain, covers the launch, who can use it, the codename question and three Meta predictions still open.

What Meta put out on 12 October

Meta's newsroom post went up at 18:08 UK time (BST). It calls the pair Meta's most capable models so far, built on the groundwork of Muse Spark. Mark Zuckerberg had announced them about 12 minutes earlier in a thread on Threads, calling Muse Wonder a much bigger and more advanced class of models than Muse Spark, with Muse Wonder pitched for speed and Muse Wonder Full as the complete model.

• What they are for. Agents that do tasks at work and at home, in fields Meta lists as law, finance, health and coding. It stresses Active Memory (keeping what matters across conversations) and Active Focus (sticking with hard tasks, checking in before big steps).
• The paperwork. Meta's model card gives 12 October 2026 as the release date. The research post credits larger, stronger base models for Muse Wonder Full handling unfamiliar tasks better than the Muse Spark 1.3 trend would suggest, and says a full safety report will follow, with no date.

Who can use Muse Wonder

Each way in that Meta describes is paid.

• Developers. Meta's developer blog of 12 October says Muse Wonder launched that day on the Meta Model API, priced per token. The API's model documentation, read on 16 October, marks it as a preview billed pay as you go and notes that availability can vary by country.
• Muse Code. Meta's terminal coding tool offers Muse Wonder on pay as you go and on every subscription plan. Muse Wonder Full is only in Muse Code, on the Power Usage and Maximum Usage plans, and not on the API.
• The Muse app. Zuckerberg wrote that people can use Muse Wonder to power their Muse by subscribing, and that Meta will work to bring this level of intelligence to everyone over time. The newsroom post is more cautious: it says Muse Wonder will soon power parts of Muse, with subscribers first.

Is Muse Wonder the Watermelon model?

Not in Meta's own words. On 16 October 2026 we read the newsroom post, the research post, the developer blog, the model card and the API documentation: none uses the word Watermelon in its text, and the only watermelon in Zuckerberg's posts is an emoji. The record around the launch:

• 2 September 2026: the Muse Spark 1.3 post said Meta's roadmap included bigger models and an open weights release of Muse Spark. Zuckerberg's Threads post that day named a watermelon emoji and the Muse Spark open weights as what comes next.
• 12 October, 16:01 UK time: nearly two hours before the launch thread, Zuckerberg posted that Muse had ordered him a watermelon, shown as an emoji.
• 12 October, 18:00 UK time: a CNBC report, drawing on an interview with Meta's chief AI officer, Alexandr Wang, described Muse Wonder as codenamed Watermelon. That is a press account of an interview, not a statement on any Meta page.
• 15 October: Meta released the open weights of Muse Spark as Muse Spark Open.

We do not say here how the prediction was decided; set these facts against its rules below.

How the Watermelon prediction was worded

Paraphrased, the rules ask for four things (what market resolution means):

• The right model. One called Watermelon, or one that Meta, or reliable outlets in broad agreement, identify as the model behind that codename, whatever its launch name.
• Public access. The general public must be able to use it. An open beta counts, and so does a waitlist anyone can join that lets people in as it goes; closed betas and private access do not.
• Clear proof. Meta announces the release, describes it clearly and says the public can use it, or the model really is public and Meta's official website labels the release plainly. A mislabelled page, filler text or a version name with no usable model behind it is not enough.
• The deadline. The end of 31 October 2026 in New York, which is 04:00 UK time on 1 November. Meta's own information comes first, with reliable reports as a cross-check.

The rules say nothing about whether access has to be free. The end date on its page is 31 October 2026; the page has shown it as settled since 13 October.

Meta predictions still open on versus

Three live predictions ask how Meta's models will rank or score; our Arena guide explains how Arena ranks models from people's votes. The readings are from 07:32 UK time on 16 October 2026 (how to read market probabilities).

• Will Meta lead the Agent Arena leaderboard on 31 Oct? The versus page showed 1.2p for Yes, the market's estimate of a 1.2% chance. It asks whether a Meta model is first in arena.ai's Agent Arena table, filtered to models, at noon New York time on 31 October (16:00 UK time, GMT). Models marked AutoEval are left out.
• Will Meta own the top text-arena model on 31 Oct? The page showed 0.4p for Yes. Same check time, on the Text Arena overall table with style control off; AutoEval models are ignored and a shared rank goes to the higher unrounded score.
• Will a Meta model hit 70% on the HLE benchmark by 31 Dec? The page showed 4.8p for Yes. Any model Meta has published must reach at least 70% accuracy on the official Humanity's Last Exam table by 23:59 New York time on 31 December, which is 04:59 UK time (GMT) on 1 January 2027.

Dates to watch

• No date yet: Meta's third quarter results. On 16 October Meta's results calendar listed no upcoming event; the last two third quarter calls were on 30 October 2024 and 29 October 2025. The safety report and the wider Muse app rollout are undated too.
• 31 October, 16:00 UK time: the Agent Arena and Text Arena checks. A Meta model in first place then means Yes for the matching prediction; any other company there means No.
• 1 January 2027, 04:59 UK time: the deadline for the benchmark prediction; a Meta model shown at 70% or more on the official table by then means Yes.

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Frequently asked questions

Has Meta released Watermelon?

Meta released Muse Wonder and Muse Wonder Full on 12 October 2026, but the text of its announcement pages does not use the codename Watermelon. A CNBC report that day described Muse Wonder as the model codenamed Watermelon.

Who can use Muse Wonder?

Developers can use it through the Meta Model API, paying as they go, or in Muse Code; in the Muse app, Zuckerberg says subscribers can use it, and Meta's newsroom post says it will reach subscribers first. Meta's documentation calls it a preview whose availability can vary by country.

What is the difference between Muse Wonder and Muse Wonder Full?

Muse Wonder Full is the higher capability version. Meta offers it only in Muse Code on the Power Usage and Maximum Usage plans, while Muse Wonder is also on the Meta Model API.

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