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eBay explicitly bans AI "buy for me" agents in user agreement update

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Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#211

Post by dspillett »

DangitBobby wrote: post #208
dspillett wrote: post #168

Earlier quoted context omitted.

> I never understood why eBay set things up to enable sniping. I've seen studies on auction method that suggest the difference in the final price (between explicit end time and the more traditional extend-until-bidding-stops method) is negligible for online auctions except in a few special cases. This is a marked difference from the expectation that, like a real-world in-person auction, the extending deadline might e…

> being able to snipe so favoured eBay with more of their attention and this brought more sellers to the platform Did they measure the impact of people who stopped using the platform due to their bids being sniped?

Unsure (those reports I read were some time ago). Though that may be another reason why the built-in snipe-like tool was added, so appease those users as well as to decrease the load imposed by external tools.

Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#212

Post by mort96 »

retsibsi wrote: post #207
mort96 wrote: post #193

Earlier quoted context omitted.

Regarding the last part: it's simple, $1.01 is less than $100 This process doesn't work endlessly. You can't just add $.01 a billion times and I'd still pay it. But it works once or twice. Shops set prices like $499.99 due to funny psychological effects: $499.99 is still a price "in the 400s" while $500 is "in the 500s". Nobody sits down and thinks logically about it and concludes that no, the $.01 difference between…

Are you: - agreeing there must be some threshold such that if the price is $X then you will buy(/bid on) the item, but if the price is $X + $0.01 then you won't; - but maintaining that in a case where you have already decided to buy/bid and the price then rises by $0.01, you will always go ahead and pay the extra cent (provided this hasn't already happened a bunch of times)? If so, then I don't see the original probl…

> are you

> - agreeing there must be some threshold such that if the price is $X then you will buy(/bid on) the item, but if the price is $X + $0.01 then you won't;

No, I'm not. If I will buy an item for price $X, I will buy the item for the price $X + $.01. The decision to purchase something is more complex and cannot be encapsulated as one single dollar value.

I think something your model fails to account for is: there is friction associated with a purchase. I will not necessarily go through the process of buying something whose "value" is $0.1 even if its price is $0.09, because there is friction to making a purchase which that $0.01 profit doesn't cover.

As an example: I recently played a Pokemon ROM hack where there was an NPC selling a nugget for 4999. You can sell the nugget for 5000. That's 1 coin profit; objectively a good trade, right? But going through the process of purchasing something isn't free. So in spite of what your economic models may suggest, I did not stop everything I was doing and spend the rest of the game buying nuggets for 4999 and selling them for 5000, because that would've been boring and my time has value.

If I've already gone through a lot of the process to decide to buy something at a certain price (which includes doing research to find out that the thing suits my needs, researching how the market looks for that category of thing, then bringing the item to the cashier or engaging in the eBay auction or contacting a seller), then I've already spent some not-insignificant amount of resources on the purchasing process. A $0.01 price increase will never be enough to stop me from completing that purchase, because $0.01 is not worth going through the whole process again.

If I'm already at the point where I want to bid on an item at $X, then I have spent more than $0.01 in effort researching things to bid on, so I would also bid $X + $0.01.

Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#213

Post by sunrunner »

jasonjayr wrote: post #187
cornholio wrote: post #159

Earlier quoted context omitted.

An alternative to ever extending the deadline is a Dutch auction model, where a bid consists of the maximum price you are willing to pay. It's a bit like integrating the snipping bot in eBay and allowing everyone to use it on fair terms. For example, suppose the current price is $1 and the current winner is someone who bid $2 as their maximum bid ceiling. If I bid a $3 maximum, then I become the winner at a price of…

Ebay works like this too. But because sniping is still permitted, I like to bid 'uncommon' amounts, like $3.17, so if someone else tried to bid a max of $3.00 even at the last moment, the bid for the few cents more wins.

  commit ecfd9009-5bae4398b13645e14ec4ce25 (HEAD -> deal-with-snipers)
  Author: sunrunner
  Date:   Thu Jan 22 13:57:34 2026 +0000

      Update BidBot default bid cents amount to be 18 (was 16), to deal with pesky sniping strategies discovered on HN.

Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#214

Post by bena »

dmurray wrote: post #96
bena wrote: post #48

Earlier quoted context omitted.

It gets into the nature of "Which grain of sand makes it a pile?" Knowing people bid snipe by bidding one cent over whole dollars, would you consistently bid two cents over if it meant you would win more of your auctions? One cent is negligible. If you asked me if I would have paid $10.01 instead of $10.00, I'd probably say "Sure". $10.02? $10.03? Like, where does the line get drawn? And then you come at it from the…

Maybe eBay should publish the price the winning bidder actually bid. This would let people stop thinking "I lost by one cent" in that situation. It also has a marketing benefit: look at all these people who got great bargains relative to what they would have paid. And it's not an unreasonable amount of transparency: in second price auctions e.g. for stamps or electricity, it's normal to publish the details of all the…

The only way to win by a cent is to put your bid at that.

If the current price is $5 and your max bid is $30 and I put a max bid of $100, it will make the current price $31 - $35, whatever the increment is.

To get ebay to accept a bid of one cent over, you have to explicitly set that. Let's say, I'd actually pay $30 as well. $30.01 isn't materially different. So if I put in $30.01, my bid becomes higher than yours.

Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#215

Post by malfist »

MarginalGainz wrote: post #180

This ban isn't about 'fairness' or bot protection; it's about protecting the Impression Funnel. Marketplaces like eBay are designed to monetize 'Wandering Attention'—sponsored listings, 'customers also bought', and sidebar ads. An AI Agent represents 'Laser Focused Attention'. It executes a transaction with zero wandering. It effectively turns the marketplace into a commoditized backend database / dumb pipe. From a G…

This reply has hallmarks of AI slop. Green name, 2x its not X its Y, em dashes.

If you want to be a productive member try commenting what you put into your prompt instead of the slop that comes out.

Also classic ai drivel: This is about protecting the business model, not their inventory. My brother in AI, eBay doesn't have inventory. They're a platform.

Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#216

Post by cat_plus_plus »

Dumbest thing in the world, not wanting buyers who are ready to complete transaction the moment they find what they want. When my car broke down and cost too much to repair I described what I need - low mileage, big trunk, 40+ MPG, under certain price, close to dealership where my broken car sat in service. That I gave the query to Grok 4 Expert (because it does heavy web scraping), found a 2020 Ford Escape Hybrid and drove it away two hours later, because rationally speaking missing a lot of work in this economy is a bigger financial risk than missing $3000 on manual bargain hunting vs a good AI hunt. If any dealers blocked scaping on sales pages, too bad for them. Speaking of which, any good bargain / secondhand market AI agent friendly API?

Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#217

Post by retsibsi »

mort96 wrote: post #212
retsibsi wrote: post #207

Earlier quoted context omitted.

Are you: - agreeing there must be some threshold such that if the price is $X then you will buy(/bid on) the item, but if the price is $X + $0.01 then you won't; - but maintaining that in a case where you have already decided to buy/bid and the price then rises by $0.01, you will always go ahead and pay the extra cent (provided this hasn't already happened a bunch of times)? If so, then I don't see the original probl…

> are you > - agreeing there must be some threshold such that if the price is $X then you will buy(/bid on) the item, but if the price is $X + $0.01 then you won't; No, I'm not. If I will buy an item for price $X, I will buy the item for the price $X + $.01. The decision to purchase something is more complex and cannot be encapsulated as one single dollar value. I think something your model fails to account for is: t…

> If I've already gone through a lot of the process to decide to buy something at a certain price [...] then I've already spent some not-insignificant amount of resources on the purchasing process.

Yes, that's part of what I was trying to account for with my second bullet point. But before you've made that initial decision, there must be some price that would cause you to make it a 'yes' and some marginally higher price that would cause you to make it a 'no'.

This value obviously won't be totally constant across time -- it will vary with your mental state. But at any given time (and for any given roll of the mental dice, if we're assuming there's some true indeterminism here), it must exist. So when we're translating from "what's the maximum I would pay" to "what should I bid", we can imagine that we're in our most rational and clear-thinking frame of mind, aren't seized by any strange impulses, and so on.

The time and effort of researching a different item also has a value that could be pinned down in a similar way. So it doesn't fundamentally change the arguments here; if product A would be worth $X in a vacuum, but you'd happily pay $Y to avoid going through the research process again, then you should bid $X+Y.

Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#218

Post by imtringued »

whyenot wrote: post #12

So scraping bots and “buy for me” bots are bad, but the incredibly annoying sniping bots are OK? That sure feels like a double standard.

I personally didn't understand why people still snipe on eBay even though they already have an automated bidding system and the reason is that you don't want to fall victim to nibblers. Nibblers are people who bid a low amount that raises the price but is unlikely to win the auction. I.e. someone bids 30€ on an item that you would bid 50€ on. This raises the price to 30€ because of your automatic bids. The nibbler then bids 35€ to see if that was enough and it still wasn't, losing you 5€ from early bidding. If the nibbler thought he could get the item for 30€, you would only have to pay 30.50€ to beat him. The other reason is that you don't want to lock up your money since a long auction timer means you can't start bidding on the next auction in case you lose.

Re: eBay explicitly bans AI "buy for me" agents in user agreement update

#219

Post by thunderfork »

And we enter the predicted cycle of "new thing that's going to Connect Everything"

Just like faxes, the internet and the world wide web, sure, this new thing Could connect everything, but that's not nearly as much of a technical problem as a sociopolitical one. Same as it ever was.

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