Architecture Decision Records

Overview

Use this skill to make architecture decisions auditable, reversible when possible, and maintainable as constraints evolve.

Scope Boundaries

• A technical decision changes long-term system direction.
• Multiple viable options exist and trade-offs must be explicit.
• Teams need a durable rationale for future reviewers.

Core Judgments

• Decision scope: what is affected and what is intentionally out of scope.
• Option set quality: whether alternatives are truly viable.
• Reversibility: cost and risk if the decision is later changed.
• Expiry/revisit trigger: what future signal should force reevaluation.

Practitioner Heuristics

• Record decisions at the same abstraction level as the problem; avoid mixing architecture and local code style debates.
• Rejected options are as important as selected ones for future context.
• State assumptions explicitly, especially around traffic, team capacity, and compliance constraints.
• Include consequences for operations and developer workflow, not only runtime behavior.

Workflow

1. Define decision question and non-negotiable constraints.
2. Enumerate realistic options and decision criteria.
3. Analyze trade-offs including failure modes and operational impact.
4. Select a decision and capture why alternatives were rejected.
5. Define measurable revisit triggers and ownership.
6. Link the record to affected architecture artifacts and implementation work.

Common Failure Modes

• ADRs describe outcomes after the fact without real alternative analysis.
• Decision records never revisit invalidated assumptions.
• Records duplicate design docs and lose decision focus.

Failure Conditions

• Stop when constraints are incomplete or contradictory.
• Stop when no meaningful alternatives are considered.
• Escalate when decision ownership and revisit triggers are undefined.