#softwarecraft

You don't practice TDD on production code. You practice on katas and bring the muscle memory to production. The gap between knowing TDD and doing TDD is reps.

Agent PR volume is up sharply and the industry response has been to deploy code-review agents to catch up. The 2026 MSR study measured what that response actually produces: 60.2% of CRA-only closed PRs sit in the 0 to 30 percent signal-ratio range. Adding a review agent to review the coding agent does not solve the volume problem; it amplifies noise the human reviewer then has to filter.

BDD wasn't a discovery. It was a rebrand of what disciplined TDD was already doing. Test data builders, factory hierarchies, and mock-driven collaboration tests are the scenarios, and they evolve alongside the code instead of rotting beside it.

Disposable tests catch this PR's regression and contribute zero to the next one. The persistent suite is a vocabulary, a contract layer, and a 10-year asset. JIT testing is a hospice plan for teams whose suites stopped compounding.

TDD's value was never that a human ran the loop. The value was the loop itself: a constrained search procedure that converges on code that is correct, named for intent, and shaped to change. Strip the human out and the discipline still works for the same reasons.

The traits the industry credentialed as senior, typing fluency and framework recall and syntax intuition, were proxies. The actual senior skill was always naming the right problem and shaping the seams that make it solvable. Agents made the proxies free; the actual skill is now visible.

A scenario factory is not setup convenience. It is a world-modeling language, and the layered grammar of object mothers, builders, and factories is the composition primitive agents recombine. Teams that hand-assemble setup hand agents nothing to build worlds from.

Agents do not bring vocabulary to your codebase. They mirror what's already there. Strong vocabulary gets agent contributions that read like the team. Weak vocabulary gets faster mediocrity. The work you did for craft reasons just became leverage.

Originally published at tddbuddy.com. This is the first post in the three-part Vocabulary Is the...

Agentic coding changes what 'good tests' means. The new floor is scenario-rich, builder-driven, domain-typed tests authored by product-thinking developers, because that's the artifact agents actually compose against.

Engineering treated product literacy as a 'nice to have', useful but not core. With agents handling translation from intent to syntax, the engineer's value lives almost entirely in the translation from business reality to correctly-named domain model. Product literacy is the part that didn't get automated.

The smartphone in your pocket contains more computing power than the Apollo 11 mission computers. Yet...