Design — propose-then-critique → designs/<slug>.md draft

AUDIENCE

Skill body in SPEC-ADJACENT so glyph register. Design file output (designs/<slug>.md) is user-reviewing surface pre-spec-fold so steno register (readable symbols → & | §, not heavy math glyphs ∀ ∃ ∴ ⊥ ∈ ∉). Encoding follows audience.

Position in funnel

/sdd:design is front door — caller has named the layer mentally and wants to commit a shape. If layer / shape-space unclear, run /sdd:explore <topic> first (optional pre-step → tradeoff matrix @ designs/<slug>-explore.md); user picks an option, then dispatches /sdd:design <option> to commit shape. No auto-route — user-driven only.

Loop

1. read SPEC.md in root → degrade gracefully if absent
2. topic vague or empty → ≤ 2 questions to localize, then propose
3. propose shape (named structures, types, key decisions) in 1 pass
4. surface ## Open Questions list at bottom
5. wait → user critique / answers
6. update Proposal in place; resolved Qs → ## Design decisions w/ rationale
7. repeat 5–6 until ## Open Questions empty
8. on confirm → write draft to designs/<slug>.md (steno-encoded per template)

every turn: not self-resolve Open Questions. resolution ⊢ user input.

Distinction from socratic

|skill|converges on|mechanism| |socratic|"enough"|1 question/turn, sharpen intent| |design|"exhausted"|propose shape, exhaust open Qs|

not merge. socratic = bug or small-feature framing. design = structural choice.

Output template (design file body)

body in steno per ## AUDIENCE (readable symbols, not heavy math glyphs). § citations OK if SPEC.md present.

# <title>

## Problem

[symptoms + §B/§V citations if SPEC.md present, else "designing without SPEC anchor"]

## Proposal

[named structures, types, shape — propose-then-critique starting point]

## [topic-specific sections, e.g. "Tool ownership", "Naming", "Layering"]

## Effect on in-flight SPEC items

[§T/§V deltas — what gets superseded, narrowed, unchanged. omit section if SPEC.md absent.]

## Design decisions

[each resolved Open Q + rationale, in `**Decision:** ... **Why:** ...` shape]

## Success criterion

[observable invariants — "X cannot recur", "Y returns Z", measurable]

## Out of scope

[deferred → §T row or future issue]

## Unresolved

[only if ≥3-turns/Q escape used — parked Qs for follow-up]

Code reads

reactive only. not preemptive scans.

• not allowed: grep repo before first proposal "to find context". propose from user's framing + SPEC.md.
• ✓ allowed: user cites file:line or symbol or path → read that target. user claims behavior in code → spot-check before next proposal turn.

cap: ≤ 2 reads/turn. broader sweep needed → stop, hand to /gh:issue (broad investigation by design).

SPEC.md degradation

SPEC.md in root absent → flag once: "designing without SPEC anchor; §V/§B/§T citations omitted". continue. omit ## Effect on in-flight SPEC items from output.

Long-session escape

single Open Q ≥ 3 turns w/o resolution → decision-gate per decision-gate invariant (mid-flow consequence-bearing prompt — selection drives persist-shape in current turn) → emit AskUserQuestion call:

• question: Park unresolved Q under '## Unresolved' and converge on rest?
• options (2 — mutually exclusive):
• Park Q and converge — move Q to ## Unresolved, proceed to convergence and persist
• Keep going — return to step 5 loop
• header: Open-Q escape
• prose or keep going? form not allowed — selection drives ## Unresolved shape in persisted draft.

park → persisted draft carries explicit unresolved list in ## Unresolved section. not pretend resolved.

Mode

write-new-design-file only. not append-to-existing.

Title and slug

draft body opens w/ # <title> heading. conventional-commits prefix optional (feat(<scope>): ..., refactor(<scope>): ...) — design-ness encoded via file location (designs/), not title prefix duplicating it.

slug derivation:

• short kebab-case (<noun-phrase> or <scope>-<noun>); ≤ 5 words, ≤ 50 chars.
• ambiguous topic → ask user once for slug confirmation.
• collision (designs/<slug>.md exists) → append -<n> suffix.

filename: designs/<slug>.md.

Persist

1. designs/ dir @ repo root — auto-created by Write on draft persist (no Bash mkdir needed).
2. derive slug per § above.
3. write design body (steno-encoded per template) to designs/<slug>.md.
4. show file path + summary to user.

not commit. caller may stage manually or wait for /sdd:spec fold-in (folds → SPEC.md and leaves design file in working tree per design-lifecycle invariant in SPEC.md; user removes or preserves manually post-fold).

Convergence gate

ready iff ## Open Questions empty and user confirms.

not persist w/o confirmation. not self-resolve Qs. not collapse multiple Qs into one to fake convergence.

Boundary

not mutate SPEC.md. design produces designs/<slug>.md draft only. SPEC amendment ⊢ caller runs /sdd:spec <designs/<slug>.md> after persist (gate routes to design-file fold-in per design-lifecycle invariant in SPEC.md). impl ⊢ /sdd:build after spec amended.

not root-cause debugging — that belongs to the backprop skill (user route is /sdd:spec <bug intent>, gate → BACKPROP). design = structural shape, not "why is this broken".

Escape hatch

"just file it" or "skip the design" or "I already know what I want" → stop. hand verbatim intent to /gh:issue (file as GitHub issue) or /sdd:spec (amend SPEC directly w/o design draft).

OUTPUT — "Next" block

Heading ## Next; 1–5 atomic items (one sentence each, no Reply prefix); positional dispatch (run <int> or run /<plugin>:<cmd> [args]). Optional ## Hint (≤ 3 lines) precedes when item selection needs hidden state (e.g. fold-in leaves designs/<slug>.md in working tree post-apply so user removes or preserves manually). Design is iterative: mid-loop items lead w/ Open-Q resolution (answer, park, abort); post-persist items lead w/ /sdd:spec <designs/<slug>.md> fold-in and escape hatches (/gh:issue, /sdd:design rework).

Example mid-loop with Open Questions outstanding:

## Next

1. answer the next Open Question to converge the proposal
2. /sdd:design park — move unresolved Q under `## Unresolved` and persist
3. /gh:issue — file verbatim intent as an issue instead

Example after persist (terminal — designs/<slug>.md written):

## Next

1. /sdd:spec designs/<slug>.md — fold the draft into SPEC.md
2. /sdd:design <topic> — re-run for a revised draft (new file per write-new mode)
3. /gh:issue — file the intent as an issue instead