If a task can be expressed as a specification plus an automated test/evaluation function, an agent can be turned on to run and iterate until the goal is achieved. The developer's critical engineering artifact therefore shifts from implementation to the objective function and test coverage.
Agent product design should center on the eval gate, not on prompting; reliability and autonomy are determined by how faithfully the evaluation measures the real objective.
The useful boundary of autonomous agency is defined by the availability and quality of a machine-checkable reward/evaluation function.
A developer writes the specification of what they want, writes a test and evaluation function, and turns on an autonomous AI agent to build and iterate until the goal is achieved.
Programmers using AI agents to write, test, and run code specifications autonomously overnight.