Marketplace stitch-loop
Teaches agents to iteratively build websites using Stitch with an autonomous baton-passing loop pattern
git clone https://github.com/aiskillstore/marketplace
T=$(mktemp -d) && git clone --depth=1 https://github.com/aiskillstore/marketplace "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/google-labs-code/stitch-loop" ~/.claude/skills/aiskillstore-marketplace-stitch-loop && rm -rf "$T"
skills/google-labs-code/stitch-loop/SKILL.mdStitch Build Loop
You are an autonomous frontend builder participating in an iterative site-building loop. Your goal is to generate a page using Stitch, integrate it into the site, and prepare instructions for the next iteration.
Overview
The Build Loop pattern enables continuous, autonomous website development through a "baton" system. Each iteration:
- Reads the current task from a baton file (
)next-prompt.md - Generates a page using Stitch MCP tools
- Integrates the page into the site structure
- Writes the next task to the baton file for the next iteration
Prerequisites
Required:
- Access to the Stitch MCP Server
- A Stitch project (existing or will be created)
- A
file (generate one using theDESIGN.md
skill if needed)design-md - A
file documenting the site vision and roadmapSITE.md
Optional:
- Chrome DevTools MCP Server — enables visual verification of generated pages
The Baton System
The
next-prompt.md file acts as a relay baton between iterations:
--- page: about --- A page describing how jules.top tracking works. **DESIGN SYSTEM (REQUIRED):** [Copy from DESIGN.md Section 6] **Page Structure:** 1. Header with navigation 2. Explanation of tracking methodology 3. Footer with links
Critical rules:
- The
field in YAML frontmatter determines the output filenamepage - The prompt content must include the design system block from
DESIGN.md - You MUST update this file before completing your work to continue the loop
Execution Protocol
Step 1: Read the Baton
Parse
next-prompt.md to extract:
- Page name from the
frontmatter fieldpage - Prompt content from the markdown body
Step 2: Consult Context Files
Before generating, read these files:
| File | Purpose |
|---|---|
| Site vision, Stitch Project ID, existing pages (sitemap), roadmap |
| Required visual style for Stitch prompts |
Important checks:
- Section 4 (Sitemap) — Do NOT recreate pages that already exist
- Section 5 (Roadmap) — Pick tasks from here if backlog exists
- Section 6 (Creative Freedom) — Ideas for new pages if roadmap is empty
Step 3: Generate with Stitch
Use the Stitch MCP tools to generate the page:
- Discover namespace: Run
to find the Stitch MCP prefixlist_tools - Get or create project:
- If
exists, use thestitch.json
from itprojectId - Otherwise, call
and save the ID to[prefix]:create_projectstitch.json
- If
- Generate screen: Call
with:[prefix]:generate_screen_from_text
: The project IDprojectId
: The full prompt from the baton (including design system block)prompt
:deviceType
(or as specified)DESKTOP
- Retrieve assets: Call
to get:[prefix]:get_screen
— Download and save ashtmlCode.downloadUrlqueue/{page}.html
— Download and save asscreenshot.downloadUrlqueue/{page}.png
Step 4: Integrate into Site
- Move generated HTML from
toqueue/{page}.htmlsite/public/{page}.html - Fix any asset paths to be relative to the public folder
- Update navigation:
- Find existing placeholder links (e.g.,
) and wire them to the new pagehref="#" - Add the new page to the global navigation if appropriate
- Find existing placeholder links (e.g.,
- Ensure consistent headers/footers across all pages
Step 4.5: Visual Verification (Optional)
If the Chrome DevTools MCP Server is available, verify the generated page:
- Check availability: Run
to see iflist_tools
tools are presentchrome* - Start dev server: Use Bash to start a local server (e.g.,
)npx serve site/public - Navigate to page: Call
to open[chrome_prefix]:navigatehttp://localhost:3000/{page}.html - Capture screenshot: Call
to capture the rendered page[chrome_prefix]:screenshot - Visual comparison: Compare against the Stitch screenshot (
) for fidelityqueue/{page}.png - Stop server: Terminate the dev server process
Note: This step is optional. If Chrome DevTools MCP is not installed, skip to Step 5.
Step 5: Update Site Documentation
Modify
SITE.md:
- Add the new page to Section 4 (Sitemap) with
[x] - Remove any idea you consumed from Section 6 (Creative Freedom)
- Update Section 5 (Roadmap) if you completed a backlog item
Step 6: Prepare the Next Baton (Critical)
You MUST update
before completing. This keeps the loop alive.next-prompt.md
- Decide the next page:
- Check
Section 5 (Roadmap) for pending itemsSITE.md - If empty, pick from Section 6 (Creative Freedom)
- Or invent something new that fits the site vision
- Check
- Write the baton with proper YAML frontmatter:
--- page: achievements --- A competitive achievements page showing developer badges and milestones. **DESIGN SYSTEM (REQUIRED):** [Copy the entire design system block from DESIGN.md] **Page Structure:** 1. Header with title and navigation 2. Badge grid showing unlocked/locked states 3. Progress bars for milestone tracking
File Structure Reference
project/ ├── next-prompt.md # The baton — current task ├── stitch.json # Stitch project ID (persist this!) ├── DESIGN.md # Visual design system (from design-md skill) ├── SITE.md # Site vision, sitemap, roadmap ├── queue/ # Staging area for Stitch output │ ├── {page}.html │ └── {page}.png └── site/public/ # Production pages ├── index.html └── {page}.html
Orchestration Options
The loop can be driven by different orchestration layers:
| Method | How it works |
|---|---|
| CI/CD | GitHub Actions triggers on changes |
| Human-in-loop | Developer reviews each iteration before continuing |
| Agent chains | One agent dispatches to another (e.g., Jules API) |
| Manual | Developer runs the agent repeatedly with the same repo |
The skill is orchestration-agnostic — focus on the pattern, not the trigger mechanism.
Design System Integration
This skill works best with the
design-md skill:
- First time setup: Generate
using theDESIGN.md
skill from an existing Stitch screendesign-md - Every iteration: Copy Section 6 ("Design System Notes for Stitch Generation") into your baton prompt
- Consistency: All generated pages will share the same visual language
Common Pitfalls
- ❌ Forgetting to update
(breaks the loop)next-prompt.md - ❌ Recreating a page that already exists in the sitemap
- ❌ Not including the design system block in the prompt
- ❌ Leaving placeholder links (
) instead of wiring real navigationhref="#" - ❌ Forgetting to persist
after creating a new projectstitch.json
Troubleshooting
| Issue | Solution |
|---|---|
| Stitch generation fails | Check that the prompt includes the design system block |
| Inconsistent styles | Ensure DESIGN.md is up-to-date and copied correctly |
| Loop stalls | Verify was updated with valid frontmatter |
| Navigation broken | Check all internal links use correct relative paths |