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Show HN: BrowseBrawl – What if browser agents battled to generate training data?

https://www.browser-brawl.com/

I remember watching the AlphaGo documentary in 2017. What stood out to me was that the model got drastically better when it started competing against itself. GANs clicked for me similarly: a generator and discriminator competing, and somehow the competition is what produces something remarkable.

I've been curious whether this principle generalizes to today's agents.

So mehulkalia and I built Browser Brawl at the YC / BrowserUse hackathon last weekend and won first place. It is a fun experiment in which an attacker agent tries to complete tasks on live websites while a defender agent injects JavaScript to sabotage it.

The analogy isn't perfect, because browser tasks aren't zero-sum. But our hypothesis is that an agent faced with an adversary should produce more interesting training data than one navigating clean, static environments.

Try it on: http://browser-brawl.com

GitHub: https://github.com/RichardHruby/browser-brawl

Demo Video: https://youtu.be/NIoFXv-JvBY

(Skip to [0:55](https://www.youtube.com/watch?v=NIoFXv-JvBY&t=55s) to see the agents “brawling” in the arena :), [1:52](https://www.youtube.com/watch?v=NIoFXv-JvBY&t=1m52s) to see the browser traces generated)

Would love to chat with anyone building or training browser agents. Happy to dive in below!

( 18 comments | 12 points | on HN )
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by rohoswagger1 on Wednesday March 04, 2026 @11:43AM (#47250128)
This is so sick! Another crazy extension could be to give them certain handicaps / abilities to add more noise
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by mehulkalia on Wednesday March 04, 2026 @11:00AM (#47249428)
Mehul here. One thing that surprised me while building this was how creative the defender agent became. It runs Claude Haiku on a timer and can choose from prebuilt disruptions like fake “Session Expired” popups, or generate custom JavaScript injections based on what the attacker is doing, like inserting fake “Search disabled” buttons. Digging through the traces and seeing the before/after screenshots of what the defender agent came up with was pretty funny, and kind of mind-blowing.
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by JosephBath on Wednesday March 04, 2026 @01:59PM (#47252169)
fascinating stuff mehul
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by etash on Wednesday March 04, 2026 @11:15AM (#47249669)
This is sick. Love the gamified creativity for the project + the actual real world usecase
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by SobjectiveTruth on Wednesday March 04, 2026 @10:31AM (#47248951)
This is hilarious
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by sohilbhatia85 on Wednesday March 04, 2026 @11:15AM (#47249671)
Super cool!!
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by julian2k on Wednesday March 04, 2026 @10:44AM (#47249171)
love it
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by mehulkalia on Wednesday March 04, 2026 @11:01AM (#47249441)
Thanks!
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by maxpowerxd on Wednesday March 04, 2026 @12:58PM (#47251284)
Woooooow
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by hgaddipa001 on Wednesday March 04, 2026 @01:05PM (#47251375)
What results have you seen so far?
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by Allstar128 on Wednesday March 04, 2026 @01:32PM (#47251758)
This is so cool!
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by JosephBath on Wednesday March 04, 2026 @02:00PM (#47252176)
this is sick
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by Daksh_Sharma1 on Wednesday March 04, 2026 @02:46PM (#47252816)
Really cool. Can’t wait to see how this grows!
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by balintpasztor on Wednesday March 04, 2026 @03:04PM (#47253036)
Awesome guys
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by hitarthkhurana on Wednesday March 04, 2026 @04:13PM (#47253938)
this is amazing!!!
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by JGitterle on Wednesday March 04, 2026 @04:30PM (#47254172)
Wow. This is cool.
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by dubious_dude on Wednesday March 04, 2026 @05:08PM (#47254633)
yoo this is sick, congrats guys!
Re:Show HN: BrowseBrawl – What if browser agents battled to ... by sghitbyabazooka on Wednesday March 04, 2026 @05:48PM (#47255074)
how much did u pay for comments?