--- name: adr-ops description: "Author, index, and lint Architecture Decision Records — append-only project memory that recovers the WHY behind a system's shape. Scaffold the next sequential ADR, enforce the canonical frontmatter + section format, manage supersession with bidirectional integrity, and treat the directory as the index. Triggers on: adr, architecture decision record, decision record, decision log, why was this decided, record this decision, supersede an adr, adr template, adr lint, adr index, docs/adr, append-only decision, new adr, next adr number." when_to_use: "Use when a change constrains future options, seriously weighed alternatives, or has rationale the code can't show — e.g. 'record this as an ADR', 'why did we decide X', 'add a decision record', 'supersede ADR-007', 'lint our ADRs', 'what's the next ADR number'." license: MIT allowed-tools: "Read Write Edit Bash Glob Grep" metadata: author: claude-mods related-skills: "git-ops, doc-scanner" --- # ADR Ops An **Architecture Decision Record (ADR)** captures one architectural decision: what was decided, why, what was rejected, and what it costs. ADRs are **append-only project memory** — they exist so a future maintainer touching a subsystem can recover the *reasoning* behind its shape without archaeology through git history or chat logs. This skill encapsulates a battle-tested ADR protocol and generalizes it to **any repo**. The default location is `docs/adr/`, but every script takes `--dir` so a repo can keep records anywhere (`docs/decisions/`, `architecture/adr/`, …). --- ## When to write an ADR Write one when a change has **any** of these properties: - It **constrains future options** — a boundary, an invariant, a "we will always / never do X" rule that later work must respect. - **Multiple alternatives were seriously evaluated** and the choice is not obvious in hindsight. - The **rationale is non-obvious from the code** — the code shows *what*, the ADR preserves *why*. Write one decision per ADR. If a change bundles two separable decisions, write two. ### When NOT to write one - A bug fix, refactor, or feature that follows existing architecture without changing it — that is a commit message. - A reversible, low-stakes choice — that is a code comment. - A point-in-time event with no forward constraint (a benchmark run, an incident write-up) — that is an audit/log entry, not an ADR. > **Rule of thumb:** if someone could plausibly undo this next month without > re-litigating a trade-off, it is **not** an ADR. --- ## Naming, location, numbering - Path: `/ADR-NNN-slug.md` (default `` = `docs/adr`). - `NNN` is zero-padded three digits, assigned **sequentially**: the next number is `highest existing + 1`. **Numbers are never reused, never reordered** — a superseded ADR keeps its number forever. - `slug` is short kebab-case naming the subject (`oauth-only-auth`, `per-trial-container`). - A protocol/how-to file (e.g. `00_*`) sorts above the numbered records and is **not** part of the sequence. ### The directory IS the index Do **not** maintain a hand-curated numbered list as the source of truth — it drifts from the filesystem. The authoritative list is the directory itself; `adr-index.sh` is just a clean parse of it. Any prose list elsewhere (README, AGENTS.md) is a convenience pointer that **may lag** and must say so. --- ## Canonical format (compact view) Full template in `assets/ADR-template.md`; full rules in `references/canonical-format.md`. The shape: ```markdown --- status: accepted date: YYYY-MM-DD supersedes: [] superseded-by: [] touches: - "path/one.py" --- # ADR-NNN: Title in Title Case ## Decision (one sentence) ## Context ## Alternatives considered ## Consequences ### Positive / ### Negative / ### Non-goals ## See also ``` **Fixed section order:** Decision → Context → Alternatives considered → Consequences → See also. Extra sections (Migration path, Enforcement, Implementation summary) go *after* Consequences. For a multi-part decision, keep the one-sentence BLUF and add a `## Decision (detail)` section lower down. ### Frontmatter fields | Field | Required | Rule | |---|---|---| | `status` | yes | `proposed` / `accepted` / `superseded` / `deprecated` (lowercase). | | `date` | yes | Decision date, `YYYY-MM-DD`. | | `supersedes` | yes | YAML list of ADR ids this replaces (`[]` if none). | | `superseded-by` | yes | YAML list of ADR ids that replace this (`[]` until superseded). | | `touches` | yes | YAML list of paths / globs / config keys this governs. **Quote each.** The grep discovery surface — `grep touches:` answers "is there an ADR about the thing I'm changing?" | | `extends` | optional | ADR ids this builds on without replacing. | | `related` | optional | Companion ADR ids (not parents). | | `deciders` | optional | Who made the call. | A new field is a protocol change — record it in a new ADR, don't invent per-record keys. --- ## Status lifecycle & immutability ``` proposed ──► accepted ──► superseded (superseded-by: [ADR-NNN]) │ └────────► deprecated (withdrawn; nothing replaces it) ``` ADRs are **append-only**. Once `accepted`, you do not rewrite the Decision or Context. Three change modes (full detail in `references/lifecycle-and-supersession.md`): 1. **Supersede** — the rule itself changes. Write a new ADR with `supersedes: [ADR-OLD]`; flip the old record's frontmatter to `status: superseded` + `superseded-by: [ADR-NEW]` in the **same commit**. Body stays intact (obsolete reasoning is itself a record). Supersession is **bidirectional** — a one-sided link is a lint error. 2. **Addendum** — new facts that refine an in-force decision. A dated `## Addendum — YYYY-MM-DD: ` at the **end** of the body. Never use it to quietly reverse the decision. 3. **In-place edit** — typos, dead links, a renamed path in `touches:`. Preserves meaning; never rewrites rationale. --- ## End-to-end workflow 1. **Scaffold** the next record: `bash scripts/adr-new.sh --dir docs/adr --title "Your decision title"` (computes `NNN = highest+1`, derives the slug, fills frontmatter). 2. **Fill it in** — BLUF first, then Context, Alternatives, Consequences, See also. Keep `touches:` accurate; it is the discovery surface. 3. **Cross-check the number** against the directory to avoid a collision with a parallel session: `ls docs/adr/ADR-*.md` (or `bash scripts/adr-index.sh`). 4. **If superseding**, flip the old record's frontmatter in the **same commit** — either by hand or with `adr-new.sh --supersedes ADR-OLD --apply-supersede`. 5. **Lint** before committing: `python scripts/adr-lint.py --dir docs/adr`. 6. **Commit** with a `docs(adr):` conventional-commit subject, e.g. `docs(adr): ADR-020 — `. --- ## Tools All scripts take `--dir` (default `docs/adr`), `--help`, and follow semantic exit codes (`0` ok, `2` usage, `3` not-found, `5` precondition, `10` findings). Pair with the `git-ops` skill for the commit/PR step. ### `scripts/adr-new.sh` — scaffold the next ADR ```bash # Next number, slug derived from the title, frontmatter pre-filled: bash scripts/adr-new.sh --title "OAuth-only auth" # Custom dir + explicit slug + proposed status, preview without writing: bash scripts/adr-new.sh --dir docs/decisions --title "Per-trial container" \ --slug per-trial-container --status proposed --dry-run # Supersede an old record and flip its frontmatter automatically: bash scripts/adr-new.sh --title "Replace router" --supersedes ADR-002 --apply-supersede ``` Refuses to overwrite an existing file (exit 5). Atomic write. `--dry-run` prints the path + rendered content and writes nothing. `--number N` forces a specific number (backfilling or coordination) — use sparingly; sequential `highest+1` is the discipline. ### `scripts/adr-index.sh` — the directory as a table (read-only) ```bash bash scripts/adr-index.sh # number | status | date | title bash scripts/adr-index.sh --json | jq '.data[] | select(.status=="accepted")' ``` Prefers `yq`; degrades to a built-in parser when yq is absent (announced on stderr). ### `scripts/adr-lint.py` — conformance validator ```bash python scripts/adr-lint.py --dir docs/adr # exit 0 clean, 10 if findings python scripts/adr-lint.py --strict --json | jq '.data[] | select(.severity=="error")' ``` Checks required + well-typed frontmatter, the `# ADR-NNN:` title matching the filename, the BLUF placement, core section order, **no duplicate numbers** (gaps are a warning), and **supersession bidirectionality** (the high-value cross-file check). `--strict` makes warnings count toward exit 10. Exit 4 if a file's frontmatter is unparseable. --- ## See also - `references/canonical-format.md` — the full template, field table, and body rules. - `references/lifecycle-and-supersession.md` — status lifecycle + the three change modes. - `assets/ADR-template.md` — copy-ready canonical template.