Confidence: medium. Evidence: case study and controlled study. Last substantive change: 2026-07.
Architecture is the set of constraints the factory must hold even as it generates code quickly. This subsystem owns those invariants: who sets them, how agents work within them, and how the system notices when structure quietly decays.
The conclusion
Humans should own the architectural invariants and trade-offs initially, and agents should explore and implement within them. Constraints need both an agent-readable explanation and a machine-enforced check, because a passing build can conceal real structural decay.
How the thinking got here
Agents first inherited human scaffolds, then generated whole repositories. That success surfaced a harder problem: architecture-smell and cognitive-debt research showed that code can pass every test while its structure erodes, its coupling grows, and its shared domain language collapses. Machine legibility improved, but machine legibility is not the same as human governability.
Credible alternatives, and when each is right
| Approach | Right when |
|---|---|
| Human architecture board | high-stakes, long-lived systems |
| Reference architectures and templates | many similar services |
| Agent-generated design with adversarial review | novel design space, strong reviewers |
| Evolutionary architecture with fitness functions | measurable non-functional goals |
Where it fails and what we still don't know
The characteristic failure is silent decay: coherence lost across months without a single red test. Large greenfield and migration successes coexist with clear evidence of architectural erosion and honest uncertainty about coherence over years. Open questions include longitudinal architecture health, decision-record quality, modularity under agent generation, reversibility, and tests for semantic and domain-model coherence.
What would change our mind
A reliable observability signal for architectural drift, one that fires before a system becomes unmaintainable, would let agents own more of the design surface safely.