Architecture decisions are often made in meetings, communicated verbally, and forgotten within weeks. When someone new joins the team or a question arises about why a particular approach was chosen, the answer is either lost or reconstructed from memory — usually incorrectly. Architecture Decision Records (ADRs) solve this problem with minimal overhead.
Decisions that disappear
Every architecture has decisions embedded in it — technology choices, integration patterns, trade-offs accepted. When these decisions aren't recorded, teams waste time re-litigating settled questions, new team members make changes that contradict previous reasoning, and nobody can explain why the system is shaped the way it is.
Lightweight by design
An effective ADR is a short document — typically one page — that captures four things: the context (what situation prompted the decision), the decision itself, the alternatives considered, and the consequences (what trade-offs were accepted). That's it. No lengthy analysis, no comprehensive evaluation matrix, no committee signatures.
ADRs live alongside the code in version control. They're numbered sequentially, immutable once accepted, and superseded rather than edited when decisions change. This creates an archaeological record of how the architecture evolved and why.
Adoption patterns
The teams that succeed with ADRs share three habits. First, they write ADRs before implementing, not after — the act of writing clarifies thinking and surfaces disagreements early. Second, they review ADRs through the same pull request workflow used for code, making them a natural part of the development process. Third, they keep the bar low — an ADR for every significant decision, not a formal process for every change.
Start with a template and three example ADRs. Once teams see how lightweight and useful they are, adoption tends to spread organically.