Executable Contracts as Guardrails for AI-Generated Code

Integrating Specmatic into my NL-to-SQL engine (DATABASE-MANAGER)

Submitted for the Specmatic Full Stack AI Engineering Intern challenge.

The problem nobody warns you about with AI coding agents

I build with AI coding agents every day — Claude Code, Cursor. They're incredible at velocity. But they have one quiet, expensive failure mode: they drift. You ask for a small change to an endpoint, and somewhere in the diff the agent renames a field, flips a status code, or drops a required parameter. The code still runs. The tests (if you have them) still pass. And then three layers downstream — in the frontend, in a consumer service — something breaks, and you spend an afternoon debugging an integration bug that was never a logic bug at all. It was a contract bug.

That's the exact problem Specmatic's challenge asked me to explore: can Spec-Driven Development and executable contracts improve AI-assisted software development? After integrating Specmatic into one of my projects, my answer is an emphatic yes — and the reason is that an executable contract is a guardrail for AI-generated code.