
AWS's Marc Brooker: Specs, Not Code, Are the Hard Part
Spec-driven development is reshaping what software engineers actually do all day, and Marc Brooker, VP and Distinguished Engineer at AWS, has read 3,000 to 4,000 postmortems that convinced him the code was never the hard part. In this episode of The AI Native Dev, Marc explains why testing and specification are now the real engineering work, why metastable failures keep taking down systems that look perfectly healthy, and why he still won't let AI write a single word of his blog. What we cover: – Why spec-driven development is turning testing into the hardest part of software – What metastable failures are, and why they keep taking healthy-looking systems down – How agentic coding tools can learn from postmortems and build their own memory – Why classic authorization breaks down once you're writing agentic policy – Why Marc won't let AI write his blog, but is fully comfortable with AI-generated code – What it takes to bring junior engineers up to speed in an AI-native industry Chapters: 00:00:00 - Introduction 00:02:17 - Marc Brooker: 18 years at AWS building agentic dev tools 00:04:36 - Inside Strands, AWS's open source agent SDK 00:06:44 - Fifteen years on call, and what agents still can't debug 00:11:23 - Metastable failures and the humility of 4,000 postmortems 00:14:32 - Teaching agents to learn from postmortems and build their own memory 00:20:14 - Why agentic policy needs more than classic authorization 00:32:14 - The agentic software development hypothesis: spec-driven development, oracles, and testing 00:39:56 - Why Marc won't let AI write his blog (but will let it write code) 00:46:37 - Advice for leveling up junior engineers in the AI era Build your software factory, one workflow at a time, with Tessl: https://tessl.co/[SLUG] 🔔 Subscribe for weekly episodes on AI-native development Do you trust an agent to run its own on-call rotation yet? Tell us in the comments.
- Transcript
- Chapters


















