How the monolith was decomposed
Extract, shim, parallel-run, cut. That pattern — applied to every service boundary — became the playbook for the entire decomposition.
They started with the integration layer: cleanest data boundaries, highest blast radius if it failed separately. Built a compatibility shim. Ran both paths in parallel for three weeks. Then cut over. Repeated for every subsequent service.
AI agents handled the tedious parts: interface contracts, integration tests for old and new paths, deployment configuration scaffolding. Humans made architectural decisions. Agents did the mechanical work that would have consumed a platform team.
The story that captures it
The existing vendor quoted a feature — a week of work, tens of thousands of dollars.
Nathan looked at the scope on a Sunday afternoon. Set an agent on it while he watched a movie with his family. Had it in a pull request by the time the credits rolled. Reviewed it Monday morning. Shipped it Monday afternoon.
The point
That is not a commentary on the vendor's competence. It is a commentary on what happens when a twenty-year engineer pairs with an agent instead of a Gantt chart.