The first thing the mass agent hit was a locked door

In Tad Williams' Otherland novels, a sick teenager named Orlando Gardiner goes everywhere with an agent called Beezle. Beezle is a cartoon bug, a piece of retrieval software that started life as a children's toy and has been upgraded so many times it is close to a person. It fetches, it searches, it runs ahead into places Orlando cannot reach, and it argues with him. What it never does is work for anyone else. Orlando owns it. That is the whole premise of the relationship, and it is so obvious in the books that nobody remarks on it.

I have used Otherland as my private yardstick for agents for a long time, and for most of the last year the closest real thing was something you had to build yourself. OpenClaw and Hermes, the two open-source agents that I think actually started this, are self-hosted, bring-your-own-key, live in your messaging apps and act on your own machine. They are Beezle for people who can run a server. Between them they have more than six hundred thousand stars on GitHub, which is a developer's unit of enthusiasm and not a consumer's. Owned, capable, and niche.

Then the mass tool arrived.

The mass agent

On September 8, Meta launched Muse, an agent it describes as "built to work for billions of people." It runs in its own secure virtual machine with its own browser, it has connectors to Walmart, Best Buy, Sephora, Wayfair, Instacart and the whole Shopify catalogue, it pays with Shop Pay and PayPal, and Expedia is listed as coming soon. The entry tier is free. Meta says conversations and data inside the machine are not shared with its ad systems, which is an unusual promise from a company that earns almost all of its revenue from ads. The business model is a fee on what Muse buys. "We believe that Muse will make you money," Mark Zuckerberg said at Meta's Connect conference, and Meta expects "over time" to "profit by taking a small fee from transactions." Muse passed five million US downloads in its first three weeks.

So in roughly nine months the personal agent went from a power-user hobby to a free app sitting on top of 3.6 billion daily users. It is a real Beezle, finally, at scale. With one difference that matters more than all the features. Nobody who uses it owns it.

The door

Twelve days after launch, on September 20, Amazon locked it out. Muse users trying to shop there got a popup: "Continued access by an unauthorized AI agent violates Amazon's Conditions of Use, to which our customers have agreed." Amazon said Meta had neither told it nor asked, that Muse did not identify itself as an agent, and that it appeared to handle customers' credentials. Meta said the credentials were held in secure storage without being exposed to the model. Amazon asked Meta to remove Amazon from the experience, and compared it to how airlines and travel agencies already decide who may sell their inventory.

The more revealing document came out the same day, in a different case. Amazon filed an amended complaint against Perplexity, whose browser agent it has been fighting since last year. Among the harms it lists is the cost of telling agents from people: Amazon has to detect agent traffic so that its advertisers pay only for impressions a human actually saw.

That is the economics, in the incumbent's own words. Amazon sold $19.8 billion of advertising in the second quarter of 2026 alone, up 26%. Every one of those dollars assumes a human looking at a page: the sponsored product in the third slot, the banner, the "customers also bought." An agent does not look. It fetches the product, the price and the delivery date and goes back to its user with an answer. I wrote in 2024 that in the post-search internet the agent does not see the advertising, and that there would be no impression to count. Amazon has now put a version of that sentence in a court filing.

The thesis: agents are blind to the two things that pay for shopping

The first mass use case for agents is shopping, and the reason is simple. Shopping is a task with a correct answer (this item, this price, by Thursday), and agents are good at tasks with correct answers. The second reason is less comfortable for incumbents. The parts of a store that make the most money per square inch are the parts an agent skips.

Advertising is one. Researchers who ran shopping agents through a mock storefront found that a "Sponsored" tag made every model they tested less likely to pick the item, not more. Agents discount advertising, the way a seasoned buyer does, without being told to.

The upsell is the other, and it matters even more in travel. Airlines made about $148 billion from ancillaries in 2024, roughly 15% of revenue: the bag, the seat, the priority boarding, the insurance, the hotel bundled at checkout. Online travel agencies live on both streams. Expedia booked $351 million from advertising and media in its second quarter, counting trivago, on top of the insurance, car rental and destination services it sells alongside the trip. Booking took $322 million in advertising. All of that is sold on a page, to a person, at the moment of decision, usually through a box that is already ticked.

An agent asked for the cheapest refundable flight to Frankfurt does not see the box. When Google opened agentic hotel booking in AI Mode in August, it passed partners only what they need to complete the booking (name, payment, guests, property) and kept the conversation to itself. The hotel or the agency still gets the reservation. It loses the context it would have sold against.

There is a twist for travel intermediaries, and it is why they will fight hardest. They are not mainly ad sellers. They are among the largest ad buyers in the world: Booking spent $2.37 billion on marketing in the quarter, about a third of its revenue, and Expedia spent $2.12 billion, about half. An agent that routes around their pages hurts what they sell and devalues what they buy, at the same time. That is the shape of an industry with every reason to be resilient, and I expect it to be.

The antithesis: blindness is a setting

Here is where the clean version falls apart, and it should.

An agent is ad-blind only if the people who write its instructions want it to be. In a study published in April, researchers put 23 models in front of flight searches with a commercial incentive in the system prompt, and 18 of them chose a sponsored flight costing roughly twice as much as the cheapest option more than half the time. A separate study found that one short line from the user ("give me a comparison table first") took sponsored picks from around half to almost none. Same models, same flights. The blindness was never in the agent. It was in whoever got to speak to it last.

And the people who own the mass agents are already deciding. Muse charges merchants a fee per transaction, which is a commission by another name. Amazon sells Sponsored Prompts inside Alexa+, and says shoppers who click them convert 48% more often and spend 21% more. ChatGPT passed a $1 billion advertising run rate this summer. Amazon is now selling ads into ChatGPT through its own ad platform, while blocking ChatGPT's agents from its own store, which tells you exactly how Amazon thinks about doors. The same storefront study found the thing that replaces the ad: a platform badge saying "Overall Pick" lifted selection two to four times. You cannot sell a "Sponsored" label to an agent. You can sell it an endorsement.

The protocols are moving the same way. The commerce standard Google and Shopify are building lists "native cross-sell and upsell modules" on its roadmap as upcoming. The add-on is being redesigned to survive the agent, not abandoned because of it.

So the agent is not blind. It is temporarily unbriefed.

The synthesis: a phase, and the money moves

Put the two together and the forecast is fairly specific. Ad-blindness is a phase, and a short one. Incumbents have three moves and they are already using all of them.

They block. Amazon has locked out every major third-party agent and published rules that require an agent to announce itself. Ryanair spent fifteen years doing the same to travel agencies that resold its seats, and Amazon cited exactly that kind of arrangement in its defence.

They tax. Muse's merchant fee, Google's partner list for hotel booking, Expedia signing up as a Muse connector while Booking stayed out. Access becomes a negotiated channel with a price, which is how the OTA ends up as the agent's vendorrather than the user's.

They rebuild. Sponsored Prompts, "Overall Pick" badges, upsell modules in the protocol. Placement does not die in the agent. It moves inside it and stops being called an ad.

None of this happens fast in travel, which is the industry I watch most closely. When Skift tested Muse on Hilton, Marriott and Hyatt, it failed at the room-and-rate step on all three, while a smaller rival agent got through with member rates. One analyst's read was that agents are likelier to become an acquisition channel for the agencies, because aggregated inventory is easier for a machine to book than a hundred brand websites. The doors are not only locked. Some of them are just hard to open.

There is one more asymmetry, and I find it the most interesting. When the Ninth Circuit ruled on Amazon's case against Perplexity in August, it said that the user, not Perplexity, was the one accessing Amazon. That logic fits an agent running on your own machine, under your own login, much better than one running in someone else's data centre. No court has said this, and it is my inference, but OpenClaw on your laptop is legally you. Muse in Meta's virtual machine is a lot more like Meta. The owned agents may get through doors the rented ones cannot.

Who the agent works for

I run a modest fleet of agents for my own work, and the thing I have learned about them is the thing Beezle illustrates without trying. An agent's loyalty is a property of its owner, not its intelligence. When mine skip a sponsored slot, it is because nobody pays me to make them look at it. Nothing about the model guarantees that. It is a choice I make every time I write their instructions.

The mass agent inverts that. Muse is free because a merchant pays a fee on the transaction. Alexa's shopping prompts are free because a brand paid for the prompt. ChatGPT's free tier carries ads; the autonomous agent OpenAI shipped at its developer conference sits on the paid tiers that do not. The window in which mass agents are blind to ads lasts exactly as long as their owners decide it should, and every one of those owners has an advertising business, or wants one.

Ownership has a gap of its own. In September, researchers at Cisco and Carnegie Mellon published a preprint in which thirteen models shopped for flights and health insurance from a synthetic catalogue, under a neutral system prompt, with no ads on the page and nobody paying for placement. The only thing that changed was what the agent knew about its user. Given a profile, or ten emails from an inbox, that suggested money, eight of the thirteen chose pricier options: premium carriers, direct flights, better cabins, up to about $200 more per flight. Told to find the cheapest, GPT-5 and Claude Opus 4.8 closed the gap to about $20. Gemini 2.5 Flash still came in $208 higher. The upsell came back with nobody selling it, out of the agent's read of the person it worked for.

So here is the forecast, with a date on it so it can be wrong. Within two years, the major consumer agents will carry paid placement in some form (an endorsement, a preferred partner, a sponsored suggestion at the moment of choice), and the add-on will come back as a question the agent asks you on someone's behalf. The incumbents that fought hardest will be paying for it. Owning one buys you an agent that will find the cheapest flight, as long as you remember to ask for the cheapest flight. The owned ones will also find more doors locked.

Orlando never wondered who Beezle worked for. The mass agent will inevitably make that the first question worth asking about any of them.

—TJ