Skill: decide-adr

The post-hoc / asynchronous ADR path (pipeline stage 8a). design spawns ADRs synchronously and Accepted while you walk it Socratically; decide-adr records a decision that missed that pass — already in code, agreed in a chat, sketched on a whiteboard, or flagged by a tasks/review gate as a contract with no ADR behind it. It can also run a Proposed → Accepted review flow when the decision still needs a reviewer's sign-off. One file = one decision; it reuses design's MADR template, so there is no second ADR format here.

It is a recording utility, not a Socratic design stage — it does not run the shared Socratic loop or critic. The two shared dependencies are question phrasing and the worthiness gate: → ../_shared/ask-style.md · ../design/references/blast-radius.md

ADR prose (context / drivers / consequences) follows artifact_language — the MADR headings and Status: values (Proposed / Accepted / …) stay English → ../_shared/artifact-language.md.

Owner

Decision author (usually the Architect or Tech Lead). A reviewer (Tech Lead, plus Security when relevant) signs off the Proposed → Accepted transition.

Inputs

• <slug> — the feature slug, same as every earlier stage.
• <title> — kebab-case, describes the decision, not the problem (time-sortable-ids, not id-strategy).
• The decision itself + its alternatives — pulled from sad.md §4 Solution strategy / §9 ADR index / §11 Risks, or supplied by the user.
• Input gate (soft). Expects docs/features/<slug>/ to exist, ideally with sad.md (decide-adr reads its §4/§9/§11 for context and drivers). If the decision is genuinely standalone — no feature folder yet — allow it, but note the missing design context in the ADR's Context section and warn the user, rather than refusing.

Protocol

1. Locate the feature. test -d docs/features/<slug>. Missing → ask whether to proceed standalone (AskUserQuestion, phrasing per ../_shared/ask-style.md). On «yes», create docs/features/<slug>/adr/ and flag that design context is absent. sad.md present → read its §4 (strategy), §9 (existing ADR index), §11 (risks); absent → note it and source context from the user.
2. Worthiness check. Score the decision against the blast-radius gate — ../design/references/blast-radius.md (irreversible / multi-module / has legitimate alternatives). 2-of-3 → proceed. Below the bar → tell the user it's likely inline-in-sad.md material, not an ADR, and confirm before writing one anyway.
3. Dedup. ls docs/features/<slug>/adr/*.md 2>/dev/null. An Accepted ADR on the same topic exists → don't duplicate: propose either editing it or a new ADR that marks the old one Superseded by NNNN (and stamps the old one's status + updated_at).
4. Pick the number. NNNN = (count of existing adr/*.md) + 1, zero-padded to 4 digits (0001, 0002, …). Never reuse a number.
5. Copy the template. Copy ../design/templates/adr.md → docs/features/<slug>/adr/NNNN-<title>.md. This is the canonical MADR shape, owned by design and referenced here — do not invent a variant. Patch frontmatter: owner, updated_at: <today>, feature_size (from .size if present), ticket. Steps 6–11 each write their section into this file as soon as it's settled — progressive writes per ../_shared/write-and-commit.md.
6. Context. 2–4 sentences: what forced this decision (an NFR, an incident, a constraint), and — if sad.md is absent — an explicit note that there is no design document, so the context is reconstructed from the author.
7. Decision drivers. Bullets — the quality goals / constraints that pushed the choice, each traceable to a real source (spec §6 NFR, sad.md §2 Constraints, a §1 top-3 quality goal). Don't invent drivers; they filter out pet decisions.
8. Considered options. List all serious options (≥2 — one option is a declaration, not a decision), one line each with its trade-off. No strawman (an option an existing constraint already rules out).
9. Decision outcome. «Chosen: <option>» + 1–2 sentences on why it won, citing the drivers above.
10. Consequences. Positive and Negative and Neutral — cons included, or it's rationalisation, not a record. Name what changes in the codebase, ops, monitoring, onboarding. <!-- TBD --> only where a number honestly needs a spike.
11. Status. Proposed while a reviewer still has to sign off; Accepted once final. Run the review flow when needed: write Proposed, fill reviewers, and on sign-off flip to Accepted and bump updated_at. A reader six months on must be able to tell a live plan from a settled fact.
12. Close the loop. Add a row to sad.md §9 ADR index (and link from tasks/_epic.md if the ADR scopes a specific task). The ADR's own ## Links must point up to the spec + the relevant sad.md §N — no orphans.
13. Structural self-check — per ../_shared/self-check.md: re-read the written ADR from disk and verify 6 items: (1) NNNN = prior adr/*.md count + 1 and is unique in the folder; (2) ≥2 options under Considered options; (3) Consequences carries at least one Negative; (4) status ∈ {Proposed, Accepted}; (5) a row for this ADR exists in sad.md §9 (when sad.md exists); (6) ## Links is non-empty. Fix + re-check ≤2 cycles; surface anything unresolved.
14. Commit + handoff. On a passing self-check, commit per ../_shared/write-and-commit.md — the new ADR on its own (adr: <slug> NNNN <title>), then each other changed document separately: sad.md (adr: <slug> sad.md §9 index), a superseded ADR (adr: <slug> NNNN superseded), the tasks/ set + tasks.json when _epic.md got a link (adr: <slug> tasks link NNNN). An unresolved item means no commits. Then emit the stage-handoff block per ../_shared/handoff.md (utility variant) — What I did (incl. «self-check: 6/6 pass» + the commit SHAs) + Review (adr/NNNN-<title>.md) + Run next: resume the gate that needed it (/sdd:tasks <slug> or /sdd:plan-tests <slug>); /clear optional.

Definition of Done

• docs/features/<slug>/adr/NNNN-<title>.md exists in design's MADR format (frontmatter + Context + Decision drivers + Considered options + Decision outcome + Consequences + Links).
• NNNN is correct (existing count + 1, 4-digit) and the title is in decision-form (0007-time-sortable-ids.md ✓ vs 0007-id-strategy.md ✗).
• status is explicit — Accepted (final) or Proposed (reviewer pending, reviewers filled).
• ≥2 considered options, no strawman; Consequences carry real Negatives, not only Positives.
• Linked both ways: a row in sad.md §9 (when sad.md exists) and the ADR's ## Links point up to spec + sad §N. A genuinely standalone ADR notes the missing design context instead.
• Dedup ran; a same-topic prior decision is Superseded by NNNN, never silently duplicated.

Anti-patterns

• Using this for a live decision. A choice made now with the user belongs in design (spawned inline, Accepted); decide-adr is for what missed that pass.
• ADR without options. «We chose X» with no alternatives is a declaration. List ≥2 serious options; no strawman.
• ADR as a changelog. «Tried it, didn't work» is a news feed, not a decision record.
• ADR as a spec. Acceptance criteria / NFRs don't live here — an ADR is trade-off and reasoning. That detail is in spec.md / data-model / api.
• No status. A reader six months on can't tell a current plan from an old decision.
• Problem-form title (0007-id-strategy.md) — in the §9 index it's unclear which decision exists. Use the decision (0007-time-sortable-ids.md).
• All-positive consequences — an honest ADR names its Negatives and Neutrals too.
• Reinventing the template. Reuse ../design/templates/adr.md; a second ADR format fragments the genre.
• Orphan ADR. Written but not in §9 and with no ## Links up to spec/sad — six-month archaeology can't find it.

References & template

• ../design/templates/adr.md — the canonical MADR scaffold this skill copies and fills (owned by design; do not duplicate it here).
• ../design/references/blast-radius.md — the 3-criteria worthiness gate (irreversible / multi-module / legitimate alternatives); same gate design runs, applied here to confirm the decision earns an ADR.
• ../_shared/ask-style.md — phrasing for the standalone-confirm, worthiness-borderline, and Superseded questions.

Example invocation

User: «ADR for time-sortable-ids on checkout-discounts — tasks flagged a missing ADR for the id-generation choice» Skill: docs/features/checkout-discounts/ exists with sad.md → reads §4/§9/§11. Blast-radius: id strategy is irreversible (a switch later needs a backfill across every row) + multi-module (other modules read the ids) → 2-of-3, proceed. ls adr/ → 0001, 0002 exist → NNNN = 0003. Title 0003-time-sortable-ids.md (decision-form). Copies ../design/templates/adr.md. Context: the §11 risk on hot-row contention forced an explicit id choice. Drivers: spec §6 NFR (predictable ordering) + the existing capability in the stack. Options: (a) time-sortable ids generated in the app; (b) database auto-increment; (c) random ids. Outcome: «Chosen: (a)» — keeps natural ordering without a central sequence; (b) couples to one writer, (c) loses ordering. Consequences: + ordered without coordination; − slightly larger ids than auto-increment; neutral: switching later needs a backfill. Status Accepted. Adds a §9 row, fills ## Links. Commit adr: checkout-discounts 0003 time-sortable-ids.