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

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