Y Combinator

The best outbound starts before you automate anything. Founders need to learn who actually has the problem, what gets their attention, and what makes them reply. YC Visiting Partner Christina Gilbert recommends doing at least your first 100 outreaches by hand so you can learn those things yourself. Drawing from her experience generating and closing millions of dollars through founder-led sales at OneSchema, Christina shares eight ways founders can improve their outbound, from targeting the right people and writing emails worth reading to following up, debugging low reply rates, and using customer language to sharpen your message. Chapters: 00:00 - Intro 00:38 - Start manual before you automate 01:25 - Targeting beats perfect messaging 02:23 - How to find the right job titles 03:07 - Picking the right companies 03:47 - Intent signals 04:25 - Craft a message worth reading 06:00 - A cold email that works 07:19 - Subject lines 07:37 - Improve your LinkedIn profile 08:47 - What your reply rates are telling you 09:47 - Follow up, and reply fast 10:37 - Block out time for outbound 11:25 - Use the messaging from your customers 12:27 - Your slog compounds Apply to Y Combinator: https://www.ycombinator.com/apply Work at a startup: https://www.ycombinator.com/jobs

Magnets are becoming critical to the future of robotics, defense, and other major US industries. But 90% of rare earth magnet material is conventionally thrown away. The team at Mass Magnetics are recycling magnets from old EV motors into new ones, with the goal of making American magnets at scale.

Introducing the YC Early Access Network. 4x a year, senior technology leaders get early looks at YC's enterprise AI companies and help shape their roadmaps. Invite-only, by application. Fall '26 kicks off Oct 22 in SF. Apply now: https://events.ycombinator.com/yc-early-access-fall-26

Harnesses get dismissed as just scaffolding, just prompt engineering, and not real research. But that couldn't be farther from the truth. The same model weights that score 30% on ARC-AGI score 95% with a better harness. So we gathered a group of researchers and founders working at the frontier to do a deep dive into the state of harnesses. We'll cover how we got to this point, the case for making your harness as expressive as possible, and what YC learned building an agent for every employee in the company. Sign up for the next Paper Club: Alternative Compute Paradigms https://events.ycombinator.com/yc-paperclub-Sep23 Chapters: 00:00 - Why harnesses matter 04:27 - Building an auto-researcher by accident 07:13 - A five minute history of harnesses 13:56 - Self-improving harnesses 17:22 - Tonight's speakers 18:35 - Seth Karten: Prime Agent, a self-improving RLM harness 21:50 - Context as an L1, L2, L3 cache 24:51 - From Turing machine to von Neumann computer 28:33 - Messaging between agents 30:04 - ARC-AGI results 33:09 - Emulator Bench and GPU kernels 37:30 - Jon Saad-Falcon: OpenJarvis, personal AI on personal devices 38:26 - How far behind are local models 39:21 - The five primitives of a personal AI stack 42:47 - Letting cloud models optimize your local stack 43:53 - 800x cheaper than the cloud 45:58 - Josh France and Regan Bell: QM, YC's agent harness for work 47:29 - A history of YC's internal agents 49:24 - OpenClaw and a fleet of 50 agents 51:04 - Pulling the brain out of the sandbox 54:43 - Letting the agent choose its own sandbox and model 57:16 - The grind tool: budgets on goals 58:50 - Agents don't understand social context Apply to Y Combinator: https://www.ycombinator.com/apply Work at a startup: https://www.ycombinator.com/jobs