Thread

Meta's Muse appears to use an OpenAI model labeled muse-special

143 points · 51 comments · Aeroi

Aeroi · 1790360286 · focus · HN ↗
author here. I kept digging through the Muse filesystem after my first post hit the front page here this week.
Going through my logs I found a background agent that used a model called azure/muse-special while building my website. I found this interesting and dug a little deeper.
The transcript and daemon binary point to an OpenAI model running on Azure. Still unclear which one or why it was selected.
The runtime also ships with an Anthropic client and a catalogue listing Claude, GPT and Kimi models. I didn’t observe Claude being used in my own sessions, but this is my Part 2 of exploring the Muse file system.
original post: <a href="https://x.com/heypeterjames/status/2103545183400800746" rel="nofollow">https://x.com/heypeterjames/status/2103545183400800746
pete at mouse dot dev
1. haolez · 1790362252 · focus · HN ↗
  Nice work!
  Are you sure this isn't just a custom model that is API-compatible with OpenAI?
  1. embedding-shape · 1790362405 · focus · HN ↗
    If it's using the same weird (and awful) "backend prompt encryption" pattern and mechanism that Codex also uses (<a href="https://news.ycombinator.com/item?id=48905028">https://news.ycombinator.com/item?id=48905028), then I'd also say it points to OpenAI being involved. Hopefully that shit isn't becoming a more popular pattern, absolutely awful for troubleshooting stuff.
    junofan · 1790364988 · focus · HN ↗
    I asked muse. It’s for codex-cli, and it routes through “OpenAI inference proxy”
    hobofan · 1790370300 · focus · HN ↗
    Anthropic does the same thing with reasoning signatures. It has already become the standard pattern.
    sellmesoap · 1790467811 · focus · HN ↗
    Oh this is like how Mozilla is in every http UA since forever?
  2. Aeroi · 1790364648 · focus · HN ↗
    I'm not no. Someone from meta would have to chime in... but its very openai shaped and served differently from all the other models listed in the daemon, under a mysterious name.
    a fine-tuned OpenAI model on Azure for the purpose of compaction or something could make sense I guess but that would still be OpenAI's weights with meta ontop, and they already have a compaction model served under azure/avocado-compaction-v1
    VygmraMGVl · 1790366977 · focus · HN ↗
    It uses a similar API to openAI. Source: <a href="https://dev.meta.ai/docs/overview" rel="nofollow">https://dev.meta.ai/docs/overview
    Source 2: I work on AI at Meta.
    verdverm · 1790369403 · focus · HN ↗
    why not the same ones, is there a unique need for a different surface?
  3. vineyardmike · 1790367411 · focus · HN ↗
    This feels like the far more likely option.
    The Muse public APIs seem to be heavily inspired by OpenAI's, they even support the richer "responses" API. They have a similarly shaped compaction API, they have the same "encrypted" reasoning. Even the Muse harness seems heavily inspired by (open source) Codex. Considering Azure's historic involvement w/ OpenAI, it seems more plausible that Azure is used as spill-over capacity, and the same Azure infra used to encrypt GPT models encrypts Muse models.
    My guess that the generally visible Anthropic/OpenAI details are leftovers from the whole meta "move fast" behavior. There are a few rough edges on the product where it leaks internal codenames (eg. signing in w/ WhatsApp required consenting to using "hatch" on one screen), so I'd believe that this was a leftover on the VM from the prototyping stage, before the Muse models were ready, or because the dev's got to benchmark against different models.
    jychang · 1790421106 · focus · HN ↗
    > The Muse public APIs seem to be heavily inspired by OpenAI's, they even support the richer "responses" API.
    ???
    Every single provider basically copy openai's api endpoint
    <a href="https://api.openai.com/v1/chat/completions" rel="nofollow">https://api.openai.com/v1/chat/completions
    <a href="https://router.huggingface.co/v1/chat/completions" rel="nofollow">https://router.huggingface.co/v1/chat/completions
    <a href="https://integrate.api.nvidia.com/v1/chat/completions" rel="nofollow">https://integrate.api.nvidia.com/v1/chat/completions
    <a href="https://generativelanguage.googleapis.com/v1beta/openai/chat/completions" rel="nofollow">https://generativelanguage.googleapis.com/v1beta/openai/chat...
    <a href="https://api.x.ai/v1/chat/completions" rel="nofollow">https://api.x.ai/v1/chat/completions
    <a href="https://api.deepseek.com/chat/completions" rel="nofollow">https://api.deepseek.com/chat/completions
    <a href="https://openrouter.ai/api/v1/chat/completions" rel="nofollow">https://openrouter.ai/api/v1/chat/completions
    <a href="https://opencode.ai/zen/v1/chat/completions">https://opencode.ai/zen/v1/chat/completions
    <a href="https://api.cerebras.ai/v1/chat/completions" rel="nofollow">https://api.cerebras.ai/v1/chat/completions
    Saying "Muse's public APIs seem heavily inspired by OpenAI" is like saying "a web server’s API seems heavily inspired by HTTP". OpenAI’s API format has become an industry standard.
    vineyardmike · 1790454999 · focus · HN ↗
    Thanks for the links to the “completions” APIs that are common. Not the “responses” API I’m talking about, however.
  4. binlog · 1790368172 · focus · HN ↗
    Why host it on Azure though?
    xmcp123 · 1790371519 · focus · HN ↗
    Microsoft owns 27% of OpenAI.
    thinkling · 1790372773 · focus · HN ↗
    I think they were asking, "If this is a model produced by Meta with an API designed to be compatible with OpenAI models, but it's not actually an OpenAI model, why is Meta hosting it on Azure?"
    losteric · 1790373263 · focus · HN ↗
    GPU compute capacity?
    cma · 1790382866 · focus · HN ↗
    Weren't they planning to sell their compute? <a href="https://www.bloomberg.com/news/articles/2026-07-01/meta-is-building-a-cloud-business-to-sell-excess-ai-compute" rel="nofollow">https://www.bloomberg.com/news/articles/2026-07-01/meta-is-b...
    I guess at peak times they might need more to the extent they offload to azure and still sell excess off peak, or some announced partners required all data stay on azure?
    [deleted] · 1790375286 · focus · HN ↗
    [deleted]
    meredithbloom · 1790378572 · focus · HN ↗
    Microsoft owns 100% of GitHub and that's hosted on AWS...
    throw03172019 · 1790380633 · focus · HN ↗
    Haven’t they been transitioning to Azure?

Open on Hacker News to reply ↗

Unofficial Hacker News client; not affiliated with Y Combinator.