Visiting Partner @ycombinator. Backing high-output YC founders via @phosphorcap. Previously founded and sold @ZeusLiving (S11) & @auctomatic (W07).
San Francisco
Joined July 2006
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Joining @ycombinator as a Visiting Partner for the Spring 2026 batch.
Feels a bit full circle.
Kulveer retweeted
You misspelled “Russia”.
Kulveer retweeted
I'd check every ML repo for code relying on SageMaker's default bucket. Older versions used a predictable S3 bucket name without checking the owner, so whoever registered it first could swap your training code and take the role's credentials. Only if your bucket didn't exist yet.
why you need @Armorer_Labs
SCOOP: Major U.S. banks are detecting unauthorized third-party AI agents inside customer accounts, including some attempting to take actions that appear to be independent of user instructions, sources told Axios.
The findings have alarmed banking executives, who are racing to restrict access to their systems as AI moves at a velocity faster than financial institutions can respond, multiple industry and bank executives told Axios.
Several banks are now preparing for worst-case and even “day after” scenarios, including how to rapidly secure or restore customer accounts if things go wrong, the people said.
Several bank executives told Axios they're struggling to distinguish between human users and AI agents. One executive said banks also struggle to determine whether agents are authorized by customers or potentially operating without their permission, more akin to rogue agent behavior.
Read my latest for Axios here: axios.com/2026/10/22/ai-agen…
Kulveer retweeted
Using Claude Code or Codex agents to automate a business workflow is like asking Newton or Einstein to solve it from first principles every time.
The AgentRun harness we built is more like an experienced analyst: it learns on the job, takes notes, and modifies its workflow after every run. That means runs get faster and cheaper over time.
Day 4 of open sourcing parts of our harness. Today we made significant improvements to our workflow DSL. We are using it in our self-improving loop - turning agentic loops into more deterministic recipes.
With these improvements (a lot of @typesafe's Jev in routing, classification, and workflow composition), we have been able to reduce the cost of agents significantly without sacrificing performance.
I meant to open source the learning loop as well, but removing the business logic from @grepdotai still needs work.
Enjoy the demo tho : )
Kulveer retweeted
Introducing Orgo: computers for agents.
Give every agent its own desktop in the cloud, ready in seconds and always on.
Already used by 1,000+ companies, and launching today with @ycombinator.
Agents are creating a revolution in how businesses operate.
They also create new surface area for hackers to infiltrate and steal valuable data.
For this new world, @Armorer_Labs has built a continuous security layer that fixes issues without interrupting the business.
Super excited to have funded @begimher and @cristian_le0 in YC's F26 batch!
They built the first AI security agent at AWS, and are bringing their expertize to the world of regulated companies.
Check it out:
armorerlabs.com/
Today @cristian_le0 and I are launching @Armorer_Labs
It finds real security issues in the AI agents that regulated companies build, and fixes them without interrupting the business.
If you lead security or engineering, book a demo at armorerlabs.com
Kulveer retweeted
1) Today we're announcing Atomwell, our state-of-the-art foundation model for predicting experimental outcomes, alongside scaling laws for molecular discovery.
We trained models from 800M to 9B parameters on ~80M experimental measurements, and found clean scaling laws in both model size and data.
Kulveer retweeted
Roadster xitter.cf/i/broadcasts/1yKAPwNgg…
Congrats on your YC launch RATLOG @_charlieweise!
An extremely fast moving, resourceful team I was very excited to fund for the F26 batch with @ycombinator.
In 4 months they went from first build to a hot-fired engine, spending under $30K.
$400M in launch reservations already signed (so much demand that they skipped the usual LOI step that hardware companies go through).
We are building reusable heavy-lift rockets to take on SpaceX, powered by an engine designed with 90% fewer parts. First engine hot-fired 4 months in, from a basement, for under $30K. $400M in launch reservations signed. Satellite operators: let’s talk @ycombinator
Kulveer retweeted
We are releasing Ultramarine 1 Flash, a frontier-class model built for knowledge work. It is open-source and achieves similar performance to Fable 5, while being 60x cheaper.
It was post-trained by a team of 5 for ~$300k all-in. Available on API now, with weights releasing in 2 weeks.
Kulveer retweeted
So glad to announce @minicor_'s $3.8M seed led by @bradgillespie at @iaventures, @ycombinator (@kul, @t_blom), with participation from @paulg
70% of the Fortune 500 run on legacy software with no APIs, making it difficult to implement AI
Minicor gives that legacy software a modern API, so enterprises can easily bring AI into the systems they already run on.
Kulveer retweeted
our agent security checker catches goal hijacking, misalignment and injection, right on your machine, 1.9ms median.
we raced it against Jev on a hard set of 25 agent attacks and 25 benign docs. Jev took 167.6ms and scored 80% accuracy, our model scored 98% while being over 88x faster.
if every agent tool call needs a security check, it can't add a network round trip each time.
Armorer Flash, recorded live at real speed
Check out @SummerEngineCom’s game audio maker
Introducing the Game Audio Maker.
Your agent can now make AAA game studio quality sound effects, music, voices and even dialogue between characters, then can wires it all into your game.
Ask your agent "Add sound effects when I jump".
Done. All through the Summer MCP.
summerengine.com/blog/make-g…
Kulveer retweeted
Introducing DeepRSI, a new industry standard for measuring recursive self-improvement.
On preexisting benchmarks, tasks are contributor-based and short-horizon (~12 hrs). In DeepRSI, we push agents to work 48 hours on ML tasks actually derived from ongoing proprietary research.
Kulveer retweeted
never giving up is crazy, like what do you mean we went from sleeping on the floor to users emailing us at 2am saying they're never going back to Salesforce.
@kul, partner at @ycombinator, told me to stop guessing and run the Superhuman PMF test. "How would you feel if you could no longer use Octolane?" The bar is 40% "very disappointed." We got 74% from [XXX] users.
@ROWGHANI at @firstharmonic told me something a while back: once you narrow down your ICP, everything else works out. He was right. If you take anything from this, it's this " Getting to PMF is a pure ICP play plus relentless iteration with a capable team"
A lot of our users are my best friends now. I take care of their dogs, help with their businesses. Recently helped one of them move apartments.
We hit PMF for a specific segment of the market and did this without any billboards, flying planes and with xero sales team. We're winning head to head against companies with 50x our resources and hot funding. Now I wake up to emails from users I've never met telling me how bad the thing they switched from was.
Now I smile on demo calls the moment someone starts talking, because I can finish their sentence before they do. Took us 2 years. Zero days off and a lot of nights I wasn't sure.
To everyone who used @octolane when it was rough, replied to my 2am emails, told me what was broken, and stayed anyway: this is yours too.
2026 brought me a lot of happiness, friendship, and late night realizations. But most importantly, it brought me a team that decided to relentlessly execute. Grateful to @vitorviesi for making sure every pixel is perfect and every detail is crafted. To Raonak, Tareq, and @yashsehgaldev for the countless all-nighters. And to my co-founder and best friend @halim__rafi , the kid on the right in the photo.
We’re just getting started.
A year ago I told @kathrynwu1, one of my closest friends from YC W24, while Jason was driving us somewhere: the day we get PMF, the only thing SF will see is Octolane.
It’s time. 🏎️🏎️🏎️
most customer success tools were built for seat-based SaaS.
usage-based companies need something vastly different.
@quivlyai is built for them.
congrats on the launch @Chandrika633 and Tanay!
they reduce the time it takes to go live with customers to 7 days and expand revenue over 4x.
@hyperspell is a very happy customer!
Today we're reintroducing @quivlyai, backed by @ycombinator.
Quivly is the AI workforce for everything after the sale, built especially for companies with usage-based pricing.
Teams using Quivly take customers live in 7 days instead of 30, then expand them 4.3x on average.
Our agents turn kickoff calls into launch plans, chase blockers, catch risk and expansion signals, and have the full account story ready at renewal.
Closing the deal is just the beginning. Quivly handles everything after that.
Kulveer retweeted
Introducing Voyager: the open harness for S-tier video, graphics and games.
The Codex for creative work.
Most AI tools are built for coding. Voyager is designed to get the best creative results from models like Opus, Astra and DeepSeek.
It comes with free graphics, music and video editing tools - or, it can drive Blender, Resolve, After Effects, Ableton and 100+ others.
Everything in this thread was made with Voyager. A few of our favorites:
