When @Felicis first invested in @Arena at the seed, we believed the company was building something essential: an independent, community-driven source of truth for measuring the AI frontier. That conviction only grew, and we went on to lead the Series A. The progress since then has been extraordinary. Arena has surpassed $100 million in annualized revenue, facilitated 350 million sessions and 62 million votes, and grown into one of the world’s largest AI communities. Today, Arena announced a $200 million Series B at a $3.1 billion valuation, alongside a new Alignment Index that measures whether AI agents behave safely, truthfully, and within the bounds of what users actually ask them to do. As AI systems begin taking real actions on our behalf, measuring capability is no longer enough. We also need to know whether these systems can be trusted. Arena is uniquely positioned to give the industry that answer, grounded in millions of real-world human interactions. We are true believers in @ml_angelopoulos, @infwinston, and the entire Arena team as they build the trusted measurement layer for AI.

What should an early-stage founder build when the models change every week? That question was at the center of our packed design conversation at Arcana, hosted by @Soleio and @Felicis. @iansilber and @joellewenstein brought perspectives shaped by work at Instagram and OpenAI, Airtable, and early Facebook. The room was full of people eager to hear what that experience means for the next generation of products. While the event discussion was off the record, there are a few takeaways worth sharing: → Build so better models make your product better, not irrelevant. → Create something that compounds beyond the model, like network effects or unique data. → Stay willing to change your mind. When capabilities shift weekly, speed of adaptation matters a lot. The design discussion stuck with me, too. We don’t fully know what these models can do yet. The people who keep experimenting (while asking what users actually want!) will be the ones to discover possibilities that no model could have predicted. Thanks to Ian, Joel, Soleio, and everyone who came ready to explore.

I used @ExaAILabs and @claudeai to draft my fantasy football team. I never opened a search engine. I did not want a list of links. I just wanted an agent to do the work with the best information possible. That is the product shift Exa is building for. We at @Felicis are true believers in @WilliamBryk, @jeffzwang, and the Exa team 🎧 cc: @tecoker

Excited to announce that Jeff Pinner has joined Exa as CTO! Jeff was formerly CTO of Robinhood, a distinguished engineer at Cruise, CTO of Lyft, and way back a systems engineer at NASA. We have humongous engineering and research to do at larger-than-google-scale and we need to do it quickly. Pinner has scaled massive ML systems before, super excited to work together on this one.

Real-world problems can’t be vibecoded. When it comes to AI companies, the tech doesn’t have an impact without the services built around it. We at @Felicis invested in a healthcare delivery platform, @joinadaptive, that understands this priority. They’re obsessed with solving the problem of how home health is delivered to patients. Companies can’t just rely on their tech alone without going the last mile. I discussed this on the More Or Less Pod hosted by @lessin, joined by friends @wolfejosh, @RachelJHolt, @scottbelsky, @SAStanford Check out the full podcast on YouTube:

What makes Ion special? He's deeply in the details. In the office every day, these days. Writing PRDs like an IC PM. Ion loves the game. Nothing/no-one is below him. Nothing is taken for granted. Here he is next to me, working on Arena, literally right now. A true 🐐

What began as a UC Berkeley research project has become one of the fastest-growing and most trusted AI infrastructure companies in the world. This week, the vision set forth by Arena founders @infwinston and @ml_angelopoulos reached another remarkable milestone: @Arena announced it has surpassed $100M in annualized revenue run rate just eight months after launching its enterprise offering, while growing to a community of more than 10 million users helping shape how frontier AI models are evaluated. In the @Felicis profile on the company, Wei-Lin and Anastasios shared how they approached building a platform rooted in scientific rigor, neutrality, and community trust; principles that have become even more important as AI capabilities accelerate. We've been true believers in Arena since Seed.

A new internet economy, built for agents: Agents break the old economics of the internet - when everyone has an AI assistant consuming and taking actions, what happens to ads? Exa Connect is a step toward a new internet economy built on data, not ads. It's a marketplace where data providers choose what to charge for their data, and developers choose which data providers their agents use. We feel this is the right economic model -- market-based, transparent, value-aligned, and as agent requests scale >1000x over the coming years, will be a more valuable market for providers than the ad market is today. This is also a good path forward for the internet. It's one that monetizes transformer attention, not human attention. We don't know exactly what that great intercontinental information exchange called the internet will become, but it's going to change, and we think very much for the better.

Tomorrow is Humans in the Loop, and we @Felicis are thrilled to featuring @extradotemail on stage as one of the companies pushing what's possible in consumer AI. @ngavini, is an n=1 leader: one of Pinterest's earliest and most tenured product execs, who helped build the company from a small startup to a public company that's defined a new kind of consumer interface. With Extra, Naveen is doing it again, but this time building an inbox for your life, starting with email. Extra takes a widespread pain of keeping up with your personal inbox and turns it into something intelligent and delightful. And today, Extra is launching "handle it". Now, you delegate tasks to Extra - whether that's scheduling a meeting, confirming an appointment, or coordinating with friends, Extra will handle the back and forth. Extra is your life’s inbox and your life’s assistant. They are also removing the waitlist; Extra is now available on iOS and web. Extra will be one of 20 companies taking the stage at Humans in the Loop in a rapid-fire demo showcase of some of the most creative, ambitious early-stage startups, all nominated by all the cohosting VC firms. Join us on June 10th!

Two in five home health patients get turned away, not because care isn't available, but because the admin overhead costs more than the agency gets paid. $40B in referrals are rejected every year. That's the problem @AlexRWendland and Ryan Tolsma are rebuilding from scratch with @joinAdaptive. AI-native operations. 100K+ visits delivered. 4.9% rehospitalization rate vs. 12.9% state average. @Felicis investors @Pxd and @EricFlaningam sat down with Alex and Ryan to discuss the future they're building with Adaptive.

“How badly do you want this deal?” Ryan, our general counsel, called me while I was at dinner. Turns out @joinAdaptive redlined the term sheet we sent them to lead their Series A, and they put in a clause that gave me second thoughts. For context: I’m a die-hard @49ers fan. Beating the Cowboys is always a good feeling. Winning the last 4 games against the Dallas Cowboys including 2 playoff games? The best. The clause they inserted was a tough one to accept. We ultimately agreed that when the company reaches a significant revenue milestone, @Felicis board members will attend a Cowboys game in Dallas with the founding team… in full Cowboys gear. Today, over 40% of patients referred to home health don’t get the care they need. Adaptive is using AI to help home health agencies serve more patients, reduce overhead, and expand access to care. AI has been transforming the digital world, but is only just beginning to change the physical world. Home health is the fastest-growing outpatient sector, on pace to nearly double over the next 5-6 years. The current foundation of fragmented small home health providers is not ready for that influx. Adaptive is rebuilding from the inside out to lay a foundation for an industry positioned to scale. I’d prefer to keep my 49ers loyalty intact. But if wearing a Cowboys jersey is the price of helping build a company that improves healthcare for millions of people, I’ll survive. To @AlexRWendland, @ryanatolsma, Logan, and Hunter, I’m rooting for you...but not your football team.

Two in every five patients referred to home health care in America never get the care they need. Not because clinicians aren't available. Not because the patient doesn't qualify. They get turned away because the paperwork costs more than the visit pays. Roughly $40B in referrals get rejected this way every year. So the agency says no, and the patient ends up in a nursing facility or gets sicker at home until the ER takes over. We led @joinadaptive's Series A because they stopped trying to sell better software to broken agencies and became the provider instead. AI runs the intake, scheduling, prior authorization, documentation, and billing that traditional agencies burn $.60 to $.90 of every clinical-labor dollar on. When those costs collapse, the patients who would have been rejected instead get the care that they deserve. So far in Adaptive's first market: Patients served by Adaptive have a 4.9% rehospitalization rate compared to the 12.9% Texas state average and 10.2% national average. More than 95% of patients see improvement in ambulation, meaning they are back on their feet, no longer homebound, compared to an 89.5% national average. Patients are set up with a home care provider extremely quickly, with 99% of patients admitted within 48 hours of referral. They have a 4.5-star CMS quality rating against an industry average of around 3. Hear from co-founders @AlexRWendland and @ryanatolsma on the future they're building with Adaptive. 👇 cc: @pxd @EricFlaningam

The @joinadaptive team is tackling one of the most important, under-the-radar problems in the American healthcare system, and we at @felicis are excited to be leading their $50M Series A.