Brief Agent Skill

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Context: this sub-skill is one lens of the broader ui-craft skill. If the ui-craft skill is also installed, read its SKILL.md first for Discovery + Anti-Slop + Craft Test, then apply the specific lens below.

Load references/brief.md for the brief format before proceeding.

Step 1: Detect existing brief

Check whether .ui-craft/brief.md exists. Use Read or ls on .ui-craft/.

If it exists: load its contents. If $ARGUMENTS names a specific update ("update principles", "shift target user", "add out of scope"), focus the session there and skip unchanged sections. Otherwise summarize what's in the brief and ask: "What do you want to change?"

If it doesn't exist: proceed to Step 2. Also check the repo root for a DESIGN.md or design-tokens.json (an ecosystem convention some teams already maintain) — if present, read it and pre-fill the brief's answers from it instead of re-asking; note the source. The brief complements an existing design contract, never contradicts it.

Step 2: Draft a new brief (absent case)

Walk the user through the five required sections in a single pass. Ask ONE compact question per section. Do not open five separate prompts unless the user asks for depth.

Compact prompt template:

> "To write your design brief I need five things — answer as tersely as you like, I'll fill in structure:

> 1. Product purpose — what does it do, in one sentence?

> 2. Primary user — who, by role and context?

> 3. Principles — what does this product believe? Give me three to five stances it takes. (If you don't have these yet, say so — I'll run the principles workshop.)

> 4. Success metric — what does 'the user succeeded on this surface' look like in observable behavior?

> 5. Out of scope — three to five things this surface deliberately does NOT do."

Principles workshop case: if the user says "I don't have principles yet" or gives vague answers ("make it good", "keep it simple"), do NOT fabricate principles from vague input. Load references/principles-catalog.md first. The catalog has 42 worked example principles across 8 product categories — use them as conversation seeds, not as templates to adopt literally. Show 2-3 from the closest category to the user's product, then ask which resonate or which they'd flip. Then run the principles workshop from references/brief.md as a focused sub-flow: ask for three past design decisions that were debated, then derive candidate principles from the patterns. Refuse to accept platitudes — push back and prompt for substance.

Parsing long input: if the user provides a product description or PRD, parse it into the five sections rather than re-asking for information already given. State what you extracted and ask for confirmation or corrections.

Thin answers: if an answer is too vague to constrain a design decision, ask one targeted follow-up. Maximum two follow-ups per section before flagging it as incomplete and moving on.

Step 3: Show before writing

Always show the proposed brief in full before writing the file. Ask: "Does this look right, or anything to adjust?"

Do not write until confirmed.

Step 4: Write the file

Create .ui-craft/ if it doesn't exist. Write the confirmed content to .ui-craft/brief.md.

The file must contain all five sections with the exact headings from references/brief.md. No omissions.

Step 5: After writing

Tell the user the file is at .ui-craft/brief.md. Suggest committing it:

> "Commit .ui-craft/brief.md to the repo — it's documentation, not config. The agent reads it every session."

Do not auto-commit. Per project rules, commits require explicit user instruction.

Constraints

• All five sections are required. If one is genuinely unknown, write it as a dated placeholder with [TO DEFINE — YYYY-MM-DD] so the gap is visible.
• The brief is append-mostly on updates. Never delete past content — mark deprecated with date and reason.
• No brand names, product examples, or generic SaaS language inside the user's brief. The brief describes their product, not the template.

Next step: /tokens — the brief decides the intent, the tokens encode it (rung 2).