Beyond the Vibes: Lessons from Using Spec Driven Development Frameworks for Agentic Coding

Spec Driven Development (SDD) promises a better approach to agentic programming in larger software projects by focusing on the what, not the how: defining requirements from which implementation can be derived. Instead of going prompt by prompt and nudging code changes, specifications clearly separate requirements from implementation and let you think in capabilities.

Historically, specs were among the lesser loved artifacts in the software lifecycle — serving mainly collaboration with other stakeholders (e.g. BDD), documentation, and compliance purposes. Now the tables might be turning, placing specs at the center of how we build software with AI agents.

In this talk, I'll compare different Spec Driven Development frameworks (such as OpenSpec, SpecKit, and others), share practical lessons from working on open source projects with them, discuss the challenges of adoption, and honestly explore when the overhead of writing specs actually pays off — and when it doesn't.