When Architecture Decisions Actually Apply
O'Reilly Radar, Tuesday, October 13th, 2026
A coding agent ignored a retrieved architecture decision, exposing the gap between relevance and authority.
Following an earlier piece on architectural guardrails for AI-generated code, the author describes a test repository where an active decision ruled out PostgreSQL, ORMs and migrations for a CLI app.
The decision was retrieved and placed in the agent's context, yet the agent still proposed PostgreSQL with an ORM.
The failure was not retrieval but a missing applicability signal telling the system that the decision governed the module being edited.
The article separates relevance from authority and guidance from enforcement, arguing that agents need both explicit scope and reproducible checks.