Architecture Decision Record

Architecture Decision Record (ADR) Skill

This skill produces a complete Architecture Decision Record (ADR) following the Nygard format — the most widely adopted standard. ADRs document the reasoning behind significant technical decisions so future team members understand not just what was decided, but why.

Required Inputs

Ask the user for these if not provided:

• ADR number (sequential number in your ADR registry — e.g. 012; or "next available" if unknown)
• Decision title (brief, e.g. "Use PostgreSQL as primary datastore")
• Context (what situation led to this decision needing to be made?)
• Options considered (at least 2; if only 1 is given, prompt for alternatives that were considered or ruled out)
• Decision made (which option was chosen)
• Reason for choice
• Status (Proposed / Accepted / Deprecated / Superseded)
• Author and date
• Team context (optional — team size, relevant experience, org constraints; helps calibrate formality and depth of the Context section)

Output Format

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ADR-[NNN]: [Decision Title]

Date: [YYYY-MM-DD] Status: [Proposed / Accepted / Deprecated / Superseded by ADR-NNN] Author(s): [Name(s)] Deciders: [Who had final say — individual or team]

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Context

[3–6 sentences. Describe the situation, constraints, and forces at play that made this decision necessary. Include: the problem being solved, relevant system state, team constraints, timeline pressures, or non-negotiable requirements. Write as if explaining to someone joining the team 18 months from now who has no prior context.]

Key constraints:

• [Constraint 1: e.g. "Must be deployable on-premise for enterprise customers"]
• [Constraint 2: e.g. "Team has no prior Go experience"]
• [Add as many as are relevant]

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Options Considered

For each option, produce:

Option [N]: [Name]

Description: [What this option is — 1–3 sentences]

Pros:

• [Pro 1]
• [Pro 2]

Cons:

• [Con 1]
• [Con 2]

Why this was ruled out (if not chosen): [Honest reason]

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Decision

We will [chosen option].

[2–4 sentences explaining the decision in plain language. This should be readable in isolation — someone should understand the decision from this paragraph alone without reading the full document.]

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Consequences

Positive Consequences

• [What this decision enables or improves]
• [What risk it mitigates]

Negative Consequences / Accepted Tradeoffs

• [What we're giving up or taking on as a result of this decision]
• [Technical debt or limitations introduced]
• [What must now be true for this decision to remain valid]

Risks

• [What could cause this decision to be wrong in hindsight]
• [What would trigger us to revisit this decision]

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Implementation Notes

[Include if the decision has non-obvious implementation gotchas, or if there are related tickets/RFCs implementers will need. Skip only if the decision is purely tooling selection with no implementation ambiguity.]

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Review Date

[Include unless the decision is permanent or self-evidently final. State a specific trigger condition — e.g. "Review if team grows beyond 20 engineers or traffic exceeds 10M requests/day" — not just "should be reviewed periodically".]

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Deeper Materials

This skill ships with support files — use them when they are available:

• references/decision-scoping.md — What Deserves an ADR (and What "Context" Must Contain). Apply it while producing the output; it carries the calibration and judgment calls the method summary above compresses.
• templates/adr.md — a fill-in version of the deliverable with the quality gates inline. Offer it when the user wants to work the document themselves rather than have it generated.