Skill: clarify

Ambiguity sweep over a written spec.md. It hunts the spec for under-specified points — vague terms, unmeasured NFRs, AC missing error/authz/edge behavior, unstated assumptions, conflicting requirements, undefined domain terms, missing actors, scope creep — then dispatches a clean-context devil's-advocate subagent that re-reads the spec fresh and answers one question: where would two engineers reasonably build different things from this? Each ambiguity it surfaces is closed with the user: either resolved (the spec is tightened in place) or deferred (a §8 Open-Questions row with owner + due). It exists so glossary / design never proceed on an ambiguous spec.

This is a sweep, not a full authoring stage — it does not run the shared Socratic loop or the coherence critic. Its shared dependencies: → ../_shared/critic.md (clean-context dispatch discipline only — the subagent here hunts AMBIGUITY, not coherence drift) · ../_shared/ask-style.md (resolve/defer question phrasing).

Depth governs how aggressively the sweep hunts + the per-finding question volume → ../_shared/interview-depth.md. (Every surfaced ambiguity is still Resolved or Deferred at every level — that's a floor, not a dial.)

Spec tightenings follow artifact_language — but the existing spec's language wins over the setting (never retro-translate mid-sweep); headings and machine tokens stay English → ../_shared/artifact-language.md.

Owner

PM + Tech Lead (the spec's co-authors resolve their own ambiguities). PM owns vague-term / scope / missing-actor calls; Tech Lead owns unmeasured-NFR / under-specified-AC / conflicting-requirement calls.

Inputs

• <slug> — same feature slug used by specify.
• Gate (hard-refuse if missing): docs/features/<slug>/spec.md. Absent → STOP and point: «run specify <slug> first — clarify sharpens an existing spec, it does not write one».
• (Optional) CONTEXT.md — two-level: read both repo-root (project-wide) and docs/features/<slug>/CONTEXT.md (feature-scoped; wins on conflict) → ../glossary/SKILL.md; if present, ## Glossary is canonical; an "undefined-term" finding for a word already glossed at either level is a false positive (drop it).
• Fast lane (XS/S): when specify produced zero §8 open questions and flagged no ambiguous AC, the skip of this stage is offered by specify's handoff (→ the fast lane in ../_shared/size-matrix.md) — the user takes it there; clarify itself never auto-skips.

Protocol

1. Gate + set interview depth. test -f docs/features/<slug>/spec.md → missing = refuse with the pointer above. Read the spec (and ## Glossary from both root CONTEXT.md and docs/features/<slug>/CONTEXT.md if present — per-feature wins — to suppress false "undefined-term" hits). Then set the interview depth (the opening question): read interview_depth from .claude/sdd.local.md if present (else default medium), and — unless a --depth=easy|medium|hard arg was passed — ask ONE depth-selection AskUserQuestion phrased per ../_shared/ask-style.md, with the saved/medium value as the «(Recommended)» first option. The level tunes how adversarially the sweep + subagent hunt (easy: only build-divergence that changes behavior, with assumptions stated; medium: balanced; hard: adversarial, every fork surfaced) and the per-finding question volume → ../_shared/interview-depth.md.
2. First-pass self-sweep. Walk the spec against the eight ambiguity classes in ./references/ambiguity-checks.md (vague-term / unmeasured-NFR / under-specified-AC / unstated-assumption / conflicting-requirement / undefined-term / missing-actor / scope-creep). Note candidate findings with a §ref each — do not edit yet.
3. Devil's-advocate subagent (the core mechanic). Dispatch the devils-advocate agent — subagent_type: "sdd:devils-advocate" (model per judgment_model, roster default opus; effort high; clean context — it never saw this conversation). Pass only the slug + the spec path; it Reads spec.md (and CONTEXT.md) itself — inline nothing — and returns "two engineers would diverge here" findings. The dispatch follows the contract in ../_shared/agent-roster.md (clean-isolated context, cited findings, NO_AMBIGUITIES if none). If devils-advocate is unavailable at runtime, fall back to a general-purpose Agent with the prompt body in ./references/ambiguity-checks.md.
4. Merge + dedupe. Union the self-sweep (step 2) with the subagent findings (step 3); collapse duplicates (same §ref + same class). Keep the highest-impact first (conflicting-requirement > under-specified-AC > unmeasured-NFR > undefined-term > missing-actor > scope-creep > vague-term > unstated-assumption). If the merged set is empty → report «spec is unambiguous», stamp nothing, suggest glossary/design.
5. Resolve or defer, per finding. For each finding, one AskUserQuestion phrased per ../_shared/ask-style.md, offering: Resolve now (user picks/dictates the tightening) · Defer to §8 (→ Open-Questions row, owner + due captured in a follow-up; missing either = stays unresolved, re-ask once) · Not an ambiguity (false positive — drop it, e.g. a term already in CONTEXT). Every finding ends Resolved or Deferred — none dangling. Depth tunes the question volume, not the floor: at easy, the skill resolves the unambiguous, low-stakes findings itself with sensible tightenings and lists them in a stated-assumptions ledger for a batch veto, asking only the behavioral/high-stakes forks; at hard, it asks every finding. The «zero dangling» rule holds at every level.
6. Write resolutions back. Apply Resolve edits in the spec's native section (tighten the §5 AC into business-observable form, replace a §6 adjective with a numeric target + measurement, fix a §1 term, add a missing §4 actor/US, cut a §3 scope-creep line). Append every Defer as a §8 checkbox row - [ ] <question>? Default now: <X>. — owner: <name/role>, due: <date or stage>. Keep a short edits-log (one line per finding: class · §ref · resolved|deferred · before→after).
   • Undefined-term findings reconcile the glossary in-flow (a hard rule, at every depth). When an undefined-term finding is Resolved, immediately invoke glossary <slug> for that term — compare it against CONTEXT.md and add/update the definition now, not as a deferred note. clarify never resolves a term by inventing a meaning inline; the canonical definition lands in CONTEXT.md so design/downstream read one source.
7. Stamp + commit. Set updated_at: <today> in the frontmatter. Re-respect specify's invariants when tightening (§5 AC stays free of HTTP/status/error-code/SQL tokens; §6 numbers carry a measurement; §4 roles only from the glossary). Propose clarify: <slug> — N resolved, M deferred. Then emit the stage-handoff block per ../_shared/handoff.md — What I did (incl. the terms already reconciled into CONTEXT.md by step 6's in-flow glossary calls — the user learns here that the glossary changed, not later) + Review (tightened spec.md, + CONTEXT.md when terms were added) + Run next — resolve the next stage per .route (Routes in ../_shared/size-matrix.md): forward /sdd:glossary <slug> ↳ or the next backbone stage to skip the glossary hop — that stage is /sdd:ux-flows <slug>, unless ux-flows' N/A condition holds (no human-facing UI — every §4 actor a system/service, or the repo has no UI at all, per the size-matrix fast lane), in which case it's /sdd:design <slug> (on quick — terms were already reconciled in-flow, so auto-resolve straight to that backbone stage unless unglossed terms remain; on full — keep both options, no auto-resolve).

Definition of Done

• Every ambiguity from the self-sweep + the subagent is Resolved (spec tightened in its native section) or Deferred (a §8 row with both owner AND due) — zero dangling.
• Resolve edits preserve specify's contracts: §5 AC carry no HTTP/status/error-code/SQL tokens, §6 NFR rows carry a numeric target + measurement (no adjectives), §4 roles match the CONTEXT glossary.
• The devil's-advocate subagent actually ran (clean context, Read the spec itself) — not skipped, not paraphrased into the main thread.
• updated_at reflects today; edits-log kept; commit proposed.
• The devil's-advocate sweep + the zero-dangling resolution rule are this skill's structural self-check (../_shared/self-check.md); its result is reported in the handoff.

Anti-patterns

• Skipping the subagent and sweeping only in-thread. The clean-context fork-finder is the core mechanic — the self-sweep is shaped by the conversation that wrote the spec and misses its own blind spots.
• Resolving an ambiguity unilaterally (no AskUserQuestion). clarify proposes; the author decides — the same user-in-the-loop contract as every SDD stage.
• Defer without owner+due — a §8 row missing either is not a real defer; re-ask once, else it stays unresolved.
• Re-running the coherence critic here. That F1–F6 cross-section drift check belongs to specify/design; clarify's subagent hunts ambiguity (build-divergence), a different target.
• Leaking implementation into a Resolve edit — tightening a §5 AC by adding a status code / endpoint / SQL detail. Stay business-observable; the technical mapping lives in api / data-model.
• Inventing answers to fill findings. A genuinely open point is deferred with an owner, not guessed — better an honest §8 row than a fabricated AC.
• Authoring new scope. clarify sharpens what the spec already says; a brand-new requirement goes back through specify, not in under cover of a "clarification".

References & template

• ./references/ambiguity-checks.md — the eight ambiguity classes (how to spot / how to resolve each) + the clean-context devil's-advocate subagent prompt body.
• ../_shared/ask-style.md — phrasing for the resolve/defer/false-positive question.
• ../_shared/critic.md — clean-context dispatch discipline reused by step 3 (Reads upstream itself, cited findings, NO_* sentinel on empty).
• ../_shared/interview-depth.md — the easy/medium/hard dial set in step 1 (sweep aggressiveness + per-finding question volume).