Anthropic’s Felix Rieseberg: Claude Cowork, Mythos, and the SaaS Extinction

Felix Rieseberg leads engineering for Claude Cowork at Anthropic, one of the most important new agentic AI products in the market today. In this episode of The MAD Podcast, Matt Turck sits down with Felix to discuss Anthropic’s newly announced Claude Mythos Preview, why Felix sees it as a genuine step-function change, and what it means when frontier AI starts showing outsized cybersecurity capabilities.

The conversation then goes deep on Claude Cowork: how it emerged from Claude Code, what the famous “10-day” story really means, why Anthropic believes AI needs access to the local computer, and how Cowork actually works under the hood. Felix explains why skills are just text files, why memory is often just text files too, and how Anthropic thinks about building trust in AI agents.

They also explore some of the biggest questions in AI product design and the future of software: why UX may matter as much as the model itself, why execution is becoming dramatically cheaper, what that means for product management and startups, and why Felix believes taste, alignment, and understanding humans may matter more than ever.

(00:00) Intro

(01:53) Claude Mythos Preview and the “step-function change”

(06:16) Why Anthropic is treating Mythos differently

(11:19) The real story behind Claude Cowork’s “10-day” build

(12:42) Why Anthropic realized Claude Code needed a non-technical version

(15:44) What Claude Cowork actually is

(17:03) Under the hood: virtual machines, tools, skills

(18:36) Where Cowork’s memory actually lives

(19:26) How Cowork connects to files, apps, and the internet

(20:45) Why Felix thinks the local computer is under-appreciated

(24:49) Trust: how do you get users comfortable with AI agents?

(28:45) What UX actually means for AI agents

(31:27) Anthropic Cowork's roadmap is only one month long

(34:12) Building 100 prototypes

(35:10) If execution is free, what becomes the bottleneck?

(37:25) Does it come down to taste?

(40:12) The hardest part of building Claude Cowork

(41:43) Advice for founders building AI agents

(44:21) SaaSpocalypse: what’s left for software startups?

(49:30) Where AI agents are going next

(51:20) Regulated industries and enterprise adoption

(54:15) Hot takes: what's underrated, overrated, and what Felix would build today