Mark Freeman, Head of DevRel at Gable, shares his Spec-Driven Development (SDD) workflow for getting consistent, reproducible results from AI coding agents. Rather than vibe coding, he invests heavily upfront in ExcaliDraw flow diagrams, JSON schemas, and detailed markdown specs using the GitHub spec-kit toolkit integrated with Claude Code. His iteration cycle is: spec → build → assess → improve spec → repeat, treating the first build as throwaway. He parallelizes work using Claude's experimental Agent Teams feature with tmux/iTerm2, then validates outcomes against specs rather than reviewing code line by line. He argues AI amplifies senior engineers more than juniors because architectural and trade-off decisions require experience that agents can't substitute. He also discusses using TypeScript for data type enforcement, integrating AI with data contracts via evals, and the future of local models running iterative agent loops as a cost-effective alternative to cloud compute.