Arthur De Los Santos

We got into @ycombinator! We: > Noticed AI can't do things for you on the web (major problem) > Turned down big tech > Locked in on this problem > Applied to YC > Graduated from MIT @RindlerAI makes every website work for any agent If you're building w/ agents, we'd love to chat!

Y Combinator @ycombinator Launches of the Week: (This round-up is for informational purposes only, and in order of the date/time of the launch, from earliest to latest.) 1) Rindler: Founded by Arthur De Los Santos @_arthurdls_ and Michael Serrano @m_y_serrano, Rindler turns any website, including sites without APIs, into a deterministic API that AI agents can reliably use. Know More At: rindler.ai 2) Control Seat: Founded by Jack Grodnick and Warren Shepard, Control Seat is the operating system for the physical world. Know More At: controlseat.com 3) Monumint @monumintcom: Founded by Tyler Maran @TylerMaran and Anna Pojawis, Monumint is Conversational AI purpose-built for financial services. Know More At: monumint.com 4) Litmus: Founded by Shaivi Rau @ShaiviRau and Elena Zhao @ElenaxZhao, Litmus @UseLitmus is the most accurate read on how an engineer actually builds. Know More At: litmushiring.com 5) Ekpa: Founded by Anant Asthana and Yuga Patel, Ekpa is building autonomous research agents for trading. Know More At: goekpa.com 6) Frigade @FrigadeHQ: Founded by Eric Brownrout and Christian Mathiesen, Frigade is an AI-powered product assistance for modern software teams. They have launched Frigade Skills: the in-app AI agent that learns your product and acts for your users. Know More At: frigade.com Post: menlotimes.com/post/y-combina… Source: ycombinator.com/launches

@ycombinator @RindlerAI @m_y_serrano We just launched on YC, appreciate any support here: ycombinator.com/launches/RHN-r…

We got into @ycombinator! We: > Noticed AI can't do things for you on the web (major problem) > Turned down big tech > Locked in on this problem > Applied to YC > Graduated from MIT @RindlerAI makes every website work for any agent If you're building w/ agents, we'd love to chat!

Checkout: rindler.ai

Ever tried to automate a real website and ended up babysitting Playwright selectors, browser-use agents, or computer-use agents? Watch me use Rindler to set up my plans for the world cup ⚽️🏆 youtu.be/V_nCIxYD-so

Fable 5 is out!

@rayanranaut I think X filters each person's feed for what they care about. There's probably a whole other side of @X we haven't seen yet

Is it me or everyone on X is a founder or aspiring to be one

@boardyai Same

I need more founders in my network

@kumesh_a @speedrun Agents should be able to operate on the web in your behalf efficiently and effectively We're building rindler.ai (YC S26), the infrastructure layer that sits on top of any website and allows AI agents to action on them in a deterministic way.

1/ Excited to announce that I’m an a16z Scout for the a16z @speedrun Fund, investing in the next wave of AI founders from day one 🚀 If you’re building something ambitious, reply below with a one-line description of what you’re building and I'll get back.

What website has the worst UI?

top 9 worst user experiences of all time: 1. GCP 2. Workday 3. X search 4. Sterling 5. X ads manager 6. Gmail search 7. Any Adobe product 8. Outlook 9. myGov australia

Has anyone tried setting up openclaw to work on the web?

I don't think many people realize how powerful claude can be with /goal Tried asking it a weird prompt to see what it would do: /goal make a baked smoothie Initially, it correctly reasoned that smoothies are blended, not baked, and made some ascii art and ingredients for the smoothie. When claude declared itself done, /goal told claude that it had not met its goal; the user asked for a baked smoothie, not a blended one. It ended up redoing the ascii into the shape of a baked potato and adjusted the instructions accordingly The lesson: Use /goal responsibly

BREAKING: U.S. to reportedly lift export controls on Anthropic’s Fable 5 as soon as tonight.

Thoughts on Sonnet 5? Doesn't quite feel like Opus 4.8 levels but its definitely an upgrade over Sonnet 4.6

@marconoiz Go is pretty good

Best Programming Language in 2026?

@GJarrosson 👋 accepted cold app here

"You need connections for YC." False. Cold apps get accepted. Every. Single. Batch. No warm intro. No insider. Just a strong application. Still not applying? You're the only barrier left.

@EOEboh If your product is that easy to copy...

Is it still safe to build in public? Since AI has made it so easy for copycats to clone your entire product and release before you can even react

Claude users, are you guys using claude skills and workflows to their true potential?

@yunadarikaa Boston, especially with the startup community coming from tnt.so

sf vs nyc for tech right now. if money and visa stuff weren’t a factor, which city are you picking and why?

Anyone building with AI agents? Or do people typically use copilot/cursor?