| name | adr-writing-weapon |
| description | Architecture Decision Records specialist — Nygard format (Context / Decision / Consequences), MADR extended template, Y-statement framing, supersession and deprecation lifecycle, Log4brains and adr-tools CLI integration, and the "decisions, not docs" philosophy. Use when authoring a new ADR, superseding an existing decision, auditing the ADR log, setting up Log4brains, or onboarding a team to ADR practice. Do NOT use for general knowledge-base authoring (library-guardian), code entity extraction (wiki-guardian), or security review of the decisions themselves (security-guardian). |
| license | MIT |
ADR Writing Weapon
Architecture Decision Records (ADRs) are the smallest useful unit of institutional memory. This Weapon encodes everything needed to author, govern, and maintain an ADR corpus: the Nygard canonical format, the MADR and Y-statement variants, the supersession lifecycle, lightweight tooling (Log4brains, adr-tools), and the "decisions, not docs" discipline that keeps ADR logs scannable and trustworthy across years of codebase evolution.
When to use this weapon
Activate when the user:
- Says "write an ADR", "record this decision", "document our architecture choice", "create an ADR for X"
- Wants to supersede an existing ADR ("we changed our minds about X", "supersede ADR-007")
- Needs to set up an ADR log from scratch ("we've never done ADRs before")
- Asks about tooling ("should we use Log4brains or adr-tools?", "how do I generate ADR HTML?")
- Wants to use ADRs for onboarding ("how do new engineers read our ADR log?")
- Asks about format choices ("Nygard vs MADR vs Y-statements?")
Do NOT activate for:
- General documentation site architecture →
library-guardian
- Per-entity code extraction into a wiki →
wiki-guardian
- Security review of an architectural decision →
security-guardian (hand off after authoring)
Playbook
| Task | Guide |
|---|
| Choose the right ADR format | guides/00-principles.md |
| Write a Nygard-style ADR | guides/01-nygard-format.md |
| Write a MADR-style ADR | guides/02-madr-format.md |
| Write a Y-statement ADR | guides/03-y-statements.md |
| Supersede or deprecate an ADR | guides/04-supersession-workflow.md |
| Set up adr-tools or Log4brains | guides/05-tooling-integration.md |
| Use the ADR log for onboarding | guides/06-adr-as-onboarding-tool.md |
For a worked end-to-end example, see examples/nygard-from-pr.md.
For blank templates, see templates/nygard.md, templates/madr.md, and templates/y-statement.md.
Core principles
1. Decisions, not docs
An ADR captures a closed, consequential decision — one that is hard or expensive to reverse and that future engineers will want to understand. It is NOT:
- A design proposal (use an RFC or PRD instead)
- A meeting summary (use a shared doc)
- A description of how something works (use the wiki)
- A changelog entry (use CHANGELOG.md)
The test: "If I delete this ADR, does the team lose understanding of why the codebase is the way it is?" If yes, write it. If no, don't.
2. Four required questions (Nygard canonical)
Every ADR must answer:
- What is the architectural context? (forces at play, constraints, the problem)
- What decision did we make? (the concrete, stated choice — no weasel words)
- What are the consequences? (positive, negative, neutral — the trade-offs accepted)
- What alternatives were considered and rejected? (and why)
3. Sequential numbering is permanent
ADR numbers are forever. They appear in commit messages (ADR-0012), code comments, PR descriptions, and onboarding docs. Never reuse, never renumber, never skip. A "deleted" ADR becomes Status: Deprecated with an explanation.
4. Supersession is bidirectional
When ADR-0025 supersedes ADR-0012:
- ADR-0025 must say
Supersedes: ADR-0012 in its header
- ADR-0012 must say
Status: Superseded by ADR-0025
Both links must be present. One-directional supersession breaks the audit trail.
5. Status lifecycle
Proposed → Accepted → Superseded (by ADR-NNNN)
→ Deprecated (rationale required)
→ Rejected (rationale required)
A Proposed ADR is in-flight. Never reference a Proposed ADR from code or other ADRs until it reaches Accepted. Never write Proposed ADRs for decisions already made.
Format comparison matrix
| Criterion | Nygard | MADR | Y-statement |
|---|
| Length | 1-2 pages | 2-4 pages | 1-5 sentences |
| Sections | Context, Decision, Consequences | Title, Status, Context, Decision, Consequences, Pros, Cons, Alternatives | Single sentence with embedded structure |
| Best for | Most team decisions | Decisions needing explicit trade-off tables | Quick records, ADR log summaries |
| Tooling | adr-tools (native) | MADR template repo | Any markdown |
| Recommended default | Yes | When alternatives are complex | As supplement to Nygard/MADR |
Recommendation: use Nygard as the default. Switch to MADR when the team needs explicit pros/cons tables (common in multi-stakeholder decisions). Use Y-statements as a one-liner summary inside Nygard/MADR, not as a standalone format.
Tooling at a glance
adr-tools (npryce/adr-tools)
The original CLI. Creates Nygard-format ADRs, handles supersession linking, generates a table of contents.
adr init docs/decisions
adr new "Use PostgreSQL"
adr new -s 1 "Use Neon instead"
adr generate toc
Log4brains (thomvaill/log4brains)
Static-site generator for ADR logs. Renders a searchable HTML knowledge base from a markdown ADR corpus. Now at v1.1.0 (December 2024). Supports mono-repo and multi-package layouts.
npx log4brains init
npx log4brains preview
npx log4brains build
npx log4brains adr new "..."
For tooling setup details, see guides/05-tooling-integration.md.
References to research
The research folder was populated by scripture-historian at normal depth (15 files, 12 external source notes). Key sources:
- Nygard original (2011, canonical):
research/external/01-nygard-original.md
- Practitioner guides 2025-2026:
research/external/02-specsource-2026.md, research/external/03-docsio-2026.md, research/external/04-archyl-2026.md
- Format comparison (arXiv 2026 empirical study):
research/external/07-arxiv-2026-adr-comparison.md
- Log4brains v1.1.0:
research/external/09-log4brains-github.md
- Google Cloud enterprise patterns:
research/external/11-google-cloud-adrs.md
- Full index:
research/index.md
- Executive summary:
research/research-summary.md
Command Brief: ai-tools/command-briefs/adr-writing-guardian-command-brief.md
Created via the Legion AI Tools Factory pipeline. Part of the Army curated by Mario Aldayuz a.k.a @thenotoriousllama.
