ADRs stored as single growing entry list until volume forces split

Context and Problem Statement

Vault ADR count starts at 0. Pre-building a per-ADR file structure would be over-engineering at that volume.

Considered Options

• Single growing list of ADR entries in one section.
• Folder-per-ADR (adr/NNNN-name.md) from day one.

Decision Outcome

Chosen option: “Single growing list”, because volume doesn’t justify separation today; ceremony without payoff at current scale. Promote to per-file ADRs when the single section becomes unwieldy — heuristic threshold ~30+ entries or when cross-referencing demand emerges.

ADHD principle: don’t optimize the system before using it.

Status update — superseded

Superseded by 0018-move-adrs-to-madr-files. By April 2026 the ADR log had grown to ~3k words across 17 entries inside README.md, making the file ~4k words total. The threshold of “unwieldy” was reached earlier than expected because the ADRs themselves grew dense (each averaged 200+ words). The new structure is per-file MADR under Atlas/References/ADR/.