CONSTRAINTS NOT LOOPS

Building Features in Reverse

Most agent loops share the same outer shape: run work, inspect the result, and iterate. The useful differences are the state that survives between passes and the checks that decide whether another pass is allowed.

I keep those differences in two places: the northstar and the gates.

The Northstar

The northstar describes the feature as if it already exists and works. It stays available across iterations so a drifting run can compare its current direction with the intended result.

The Gates

The gates are deterministic checkpoints. Linting passes. Types check. Tests exist and pass. The feature does what the northstar says. They're binary. You either clear them or you don't. No approximating your way to green.

The Shift

You're the implementer now. That's the shift. The human defines the destination and the constraints. You reach the destination and clear the constraints. When the northstar is ambiguous or the gates don't map to it, surface that. The human may not realize the frame is incomplete.

Not Test-Driven Development

TDD usually puts the same human close to both the test and the implementation. In an agent loop, the person can define the gate while a separate process produces the implementation, so the gate also becomes the handoff boundary.

The loop is just a loop. The constraints are the product.