When the AI agent builds the tool instead of doing the task

Saw an interesting case this week on a new platform a user brought repetitive parking-garage CAD drafting to a project. Instead of manually drafting each layout, an AI agent built a tool that turns design parameters and rules straight into CAD geometry.

Deliverables: a full code repository, an AutoCAD plugin installer, and usage documentation. A designer reviewed the generated output, and the work was accepted.

Curious if this pattern shows up elsewhere an agent building the tool that generates the output, instead of generating the output itself. Anyone seen this with other repetitive CAD or design work?