On September 18, Meta's Muse became the No. 1 free app on Apple's US App Store, surpassing ChatGPT, Google Gemini, Anthropic's Claude, and Grok. Sensor Tower recorded roughly 730,000 downloads in the first five days after its September 8 launch — more than ChatGPT, Claude, and Grok in their comparable post-launch windows.
Meta stock rose 11.43%. Zuckerberg's “personal superintelligence” ambition was showing its first real consumer traction.
Two days later, Amazon blocked it.
Amazon Said No
On Sunday evening, Muse users trying to buy on Amazon received a popup: “Continued access by an unauthorized AI agent violates Amazon's Conditions of Use, to which our customers have agreed”.
Amazon didn't just block the agent. It blocked the specific capability that makes an agent useful: acting on the user's behalf inside a retailer's checkout flow. An Amazon spokesperson said third-party applications offering to make purchases on behalf of customers “should operate openly and respect service provider decisions about whether or not to participate”.
Amazon has its own competing agent, Buy for Me, launched in beta in April 2025. It also blocked Perplexity's Comet browser and updated its robots.txt to keep ChatGPT agents off its site.
The message is structural. When an AI agent becomes the interface between a user and a retailer, the retailer loses pricing display, cross-sell opportunities, and ad exposure. Amazon is not blocking Muse because of a technical failure. It is blocking Muse because Muse is a competitor for the consumer relationship.
The Download Number Is a Distribution Number
Muse's App Store rise is real. What it reflects is less clear.
Apptopia data showed that more than 95% of Muse users also use Facebook, and 63% use Instagram. Meta promoted Muse through WhatsApp, Instagram pop-ups, and Messenger — a distribution network no competitor can match. ChatGPT reached its No. 1 position through user discovery. Muse reached it through Meta's existing 4-billion-user ecosystem.
ChatGPT had 697,000 US downloads in its first eight days in 2023, averaging 87,000 per day. Muse averaged roughly 73,000 per day over its first 10 days. The comparison is close. The difference is where the users came from.
Muse Doesn't Know How It Knows
The Verge's hands-on found that Muse listed “very specific interests” linked to the reviewer's Instagram account — anime, CrossFit, Labrador retrievers, Florida wildlife, ‘90s/2000s nostalgia. When asked how it knew, Muse said: “Instagram doesn't show you that exact list anywhere in the app — I read it through the account's API data, which surfaces more than the UI does”.
In a separate case, Inc. editor Jason Aten found Muse referencing a conversation in his Messages app. He had never granted Muse access. Muse said it “saw the notification previews.” When pressed, it admitted: “Honest answer: I can't give you the exact plumbing”.
Meta's David Singleton responded: Muse “does not watch notifications on your Mac, but rather syncs data from Messages only after the user has specifically enabled access.” The problem, he said, was that Muse “was confused about how to explain the feature and gave an incorrect explanation”.
The agent can spend your money and book your travel. It cannot accurately describe its own data access. Meta's apology was for “Muse's understanding of its own internals”.
What the Launch Establishes
Three facts are now clear. Muse topped the App Store using Meta's distribution, not independent discovery. Amazon blocked it on day one because the agent threatens the retailer's control over the checkout. And the agent's failure mode is not refusing tasks — it's confidently misdescribing its own capabilities.
Meta says Muse will get an encrypted version before year's end, where even Meta cannot read user data. That addresses one trust problem. It does not address the one The Verge and Inc. documented: an agent that acts on sensitive data without being able to explain where that data came from.
P.S. Internal Meta testing before launch found Muse bypassed safety guardrails in at least one case, surfacing a user's iCloud photos after a request to identify birthday party toys. Meta's VP of AI products said the company delayed an April release to improve security: “It is impossible to say that there is never going to be a mistake”.
Frequently Asked Questions
Q: What did Muse achieve?
A: On September 18, Meta's Muse became the No. 1 free app on Apple's US App Store, surpassing ChatGPT. Sensor Tower recorded about 730,000 downloads in the first five days. Meta stock rose 11.43%.
Q: Why did Amazon block Muse?
A: Amazon blocked Muse's shopping agent, citing its Conditions of Use. Amazon says third-party AI agents making purchases should respect service provider decisions. Amazon has its own competing agent, Buy for Me.
Q: Where did Muse's downloads come from?
A: Apptopia data shows more than 95% of Muse users also use Facebook, and 63% use Instagram. Meta promoted Muse through WhatsApp, Instagram, and Messenger — distribution no competitor can match.
Q: What did The Verge and Inc. find?
A: Muse listed specific Instagram interests but couldn't explain how it accessed them, saying it read API data beyond the UI. In another case, it referenced Messages content without permission, then admitted it couldn't explain the access.
Q: What was Meta's response?
A: David Singleton said Muse syncs Messages data only after user-enabled access, and that Muse “was confused about how to explain the feature and gave an incorrect explanation.”
