Practice : Architectural Decision Records (ADRs)

Purpose and Strategic Importance

Architectural Decision Records (ADRs) reduce risk, improve alignment, and support system evolution by capturing the rationale, trade-offs, and context behind major technical decisions. By making decisions explicit, teams improve knowledge sharing, reduce ambiguity, and create a living history that informs future work.

Without ADRs, technical decisions become opaque, hard to trace, and vulnerable to repeated debate or reversal, increasing delivery risk, system inconsistency, and technical debt.

Description of the Practice

  • ADRs are lightweight, version-controlled documents that record key technical decisions, alternatives considered, and reasoning.
  • Records are created at the time of decision, not retroactively.
  • ADRs focus on decisions with architectural, systemic, or long-term impact.
  • Documentation is accessible to all teams and informs future system evolution.

How to Practise It (Playbook)

1. Getting Started

  • Agree on a simple, consistent ADR format (e.g. status, context, decision, consequences).
  • Store ADRs alongside source code or in shared technical documentation repositories.
  • Start recording decisions for significant architectural or systemic changes.
  • Promote a culture where decisions are shared, not hidden.

2. Scaling and Maturing

  • Integrate ADR discussions into technical design reviews and architectural forums.
  • Encourage collaborative authorship and peer review of ADRs.
  • Link ADRs to system documentation, diagrams, and relevant code changes.
  • Periodically review and retire obsolete ADRs to maintain relevance.

3. Team Behaviours to Encourage

  • Treat ADRs as enablers of clarity and learning, not as bureaucracy.
  • Capture decisions early to reduce uncertainty and rework.
  • Use ADRs to promote shared understanding and reduce tribal knowledge.
  • Reflect on the consequences of past decisions to inform future choices.

4. Watch Out For…

  • ADRs that are too detailed, vague, or inconsistently maintained.
  • Teams avoiding ADRs due to perceived overhead or lack of value.
  • Decisions made without visibility or traceability.
  • Outdated or unmaintained ADRs creating confusion.

5. Signals of Success

  • Key technical decisions are recorded, accessible, and understood by teams.
  • Decision-making becomes more transparent, structured, and evidence-based.
  • Teams reduce repeated debate, uncertainty, and delivery friction.
  • System design evolves with clarity, confidence, and reduced risk.