Visual Prototype Gate

Position in workflow: v0.4 Screen Flow Definition → v0.4 Visual Prototype Gate → v0.5 Red Team Review

Screens on paper are hypotheses. Screens rendered visually are testable. This skill converts SCR- entries into structured prompts for Google Stitch (or any UI generation tool), then captures feedback routed back to specific SoT IDs.

Rule: No product advances past v0.4 without a visual prototype reviewed by at least one stakeholder.

Consumes

• SCR-* entries (from Screen Flow Definition) — Each SCR- becomes one Stitch prompt. 1:1 mapping, no exceptions.
• PER-* entries (from Persona Definition) — User context shapes copy, complexity, and emotional framing per screen.
• UJ-* entries (from User Journey Mapping) — Journey position determines each screen's emotional beat (uncertainty → clarity → confidence).
• DES-* entries (from Screen Flow Definition) — Shared components referenced in prompts for visual consistency.
• BR-* business rules — Constraints affecting visual layout (pricing tiers, role-based visibility, data rules).

Produces

• Stitch Prompt Block per SCR- — One structured prompt per screen, ready to paste into Stitch. Grouped by UJ- journey for context.
• Prototype Context Brief — Product context + design style preamble (pasted once into Stitch before screen prompts).
• Feedback Capture Template — Table mapping each prototype screen to its SCR- ID for structured review. See assets/feedback-capture-template.md.
• No new SoT IDs — This skill visualizes existing IDs. Feedback routes back to SCR-, DES-, or CFD- entries.

Step-by-Step Process

Step 1: Confirm Inputs Exist

Check that Screen Flow Definition is complete:

• At least 3 SCR- entries exist with Purpose, Key Elements, and Related IDs populated
• At least 1 UJ- journey references those screens
• Design style preference confirmed with user (or default: "Clean B2B SaaS, minimal, professional")

If SCR- entries are incomplete, stop and run prd-v04-screen-flow-definition first.

Step 2: Write the Prototype Context Brief

One block, written once per product. This is pasted into Stitch as the opening context before individual screen prompts.

PRODUCT CONTEXT
[2-3 sentences from PRD v0.1 Spark: what the product is, who uses it, what pain it solves]

PRIMARY USER
[From PER-001: role, context, technical comfort level]

DESIGN STYLE
[Confirmed aesthetic — e.g., "Clean B2B SaaS, dark sidebar, minimal. Color for status only."]

Step 3: Generate Per-Screen Prompts

For each SCR- entry, produce one Stitch prompt block. Follow this template:

SCREEN: [SCR-XXX] — [Screen Name]
Journey position: [UJ-XXX], Step [N] of [Total]
User goal: [From SCR- Purpose field]
Situation: [What just happened — derived from prior UJ- step]
Key UI elements: [From SCR- Key Elements, using specific UI/UX keywords]
  - [Element 1: be specific — "green 'Run' button, top right, disabled until selection made"]
  - [Element 2: reference DES-XXX if shared component]
  - [Element 3+]
Constraints: [BR-XXX rules affecting this screen — e.g., "free tier sees max 3 items"]
Emotional beat: [Derived from journey position — early=uncertainty, mid=engagement, end=confidence]
Layout: [UI surface type — full page, sidebar panel, modal, card grid, etc.]

Stitch-specific guidance (from research):

• Use UI/UX keywords: "navigation bar," "card layout," "call-to-action," not vague terms like "a button"
• One screen per Stitch generation for best results — do not combine multiple SCR- entries into one prompt
• Include adjectives for aesthetic: "minimal," "clean," "dark," "warm" — Stitch uses these for palette and typography
• Reference specific positions: "top-right," "below the header," "spanning full width"

Step 4: Identify the Money Shot

Select the single screen that communicates core product value fastest. This is typically the screen at the UJ- "Moment of Value" step. Mark it in the output. This frame gets screenshotted for any stakeholder deck, landing page, or pitch.

Step 5: Output Feedback Capture Template

Alongside prompts, output the feedback capture template (see assets/feedback-capture-template.md). This is the structured review artifact — reviewers annotate per-screen, feedback routes to specific IDs.

Stitch Workflow Notes

Google Stitch iterates best with incremental refinement:

1. Paste the Prototype Context Brief first
2. Generate one screen at a time using per-screen prompts
3. Refine each screen with targeted follow-ups ("Move the CTA to the right," "Change card layout to 2-column grid")
4. Export to Figma if design iteration continues beyond prototype stage

For non-Stitch tools, see references/tool-adaptation-notes.md.

Quality Gates (v0.4 → v0.5 Readiness)

Before proceeding to v0.5 Red Team Review:

• All SCR- entries have a corresponding visual prototype screen
• At least one stakeholder has reviewed the prototype
• Feedback Capture Template is completed with disposition for each item
• Money Shot identified and captured

Downstream Connections

Consumer	What It Uses
v0.5 Red Team Review	Visual prototype informs risk assessment — "does this feel buildable?"
v0.6 Architecture	Validated screens inform API data requirements
v0.7 Build Execution	Prototype becomes the visual spec for implementation
Stakeholder Communication	Money Shot used in decks, pitches, landing pages

Detailed References

• Feedback capture template: See assets/feedback-capture-template.md
• Tool adaptation notes: See references/tool-adaptation-notes.md
• Screen count guidelines: See references/screen-count-guidelines.md