Stitch Build Loop

This skill is a catalog-normalized import from https://github.com/google-labs-code/stitch-skills at commit 7b53207b94e62911777d53d4238b5f8c88c2b519, source path plugins/stitch-utilities/skills/stitch-loop. The upstream control file was corrected for this workspace: the verified Stitch MCP surface here is design-system oriented, so screen lookup, screen generation, and screen editing tools must be used only when the current host explicitly exposes them.

When to Use This Skill

Use when a multi-page site should be built iteratively with Stitch and baton files.
The task involves Google Stitch project IDs, .stitch/ artifacts, DESIGN.md files, Stitch exports, or Stitch-specific validation.
The broader stitch-design router points here as the narrowest workflow.

Workflow

Read .stitch/next-prompt.md, .stitch/SITE.md, and .stitch/DESIGN.md before generating or integrating pages.
Use stitch-generate-design for screen prompts when tools or the Stitch web UI are available.
When screen-generation MCP tools are absent, prepare the next prompt and record that the web UI/API step is required.
Move generated or exported HTML into the site only after checking the sitemap.
Run local browser verification when a page is integrated into a runnable site.
Update SITE.md, metadata, and next-prompt.md before closing the loop.

Local Assets

examples/, resources/, references/, or reference/ are upstream support material when present. Treat SKILL.md as the source of truth if a support file mentions an unavailable MCP tool.
scripts/ are optional helpers. On Windows, prefer PowerShell or Node equivalents unless Git Bash or WSL is actually available.
Keep generated .stitch/ files out of commits unless the user explicitly wants them as durable examples.

Corrected Stitch MCP Surface

Verified in this workspace on 2026-06-15: create_project, upload_design_md, create_design_system_from_design_md, list_design_systems, and apply_design_system. This 2026-07-29 source refresh did not re-verify a broader live MCP surface. Do not claim list_projects, list_screens, get_project, get_screen, generate_screen_from_text, edit_screens, or generate_variants were used unless the current host exposes those exact tools in the active tool list.

Cross-Client Portability

This skill is written to stay usable across GitHub Copilot, Claude Code, and Codex.

GitHub Copilot: keep the folder in a Copilot-visible skill path or wrap the workflow in project instructions when folder discovery is unavailable.
Claude Code: keep the folder in a local skills directory or a compatible plugin source.
Codex: install or sync the folder into $CODEX_HOME/skills/stitch-loop and restart Codex after major changes.

MCP Availability And Fallback

Preferred MCP Server: Stitch MCP

Fallback prompt: "Use the Stitch Build Loop skill without MCP. Follow the documented local or manual fallback, show the selected tool surface, and report the verification evidence."
Use local .stitch/ artifacts, exported HTML or screenshots, bundled scripts, and the Stitch web UI when the host does not expose the needed Stitch MCP operation.
Do not claim screen lookup, generation, editing, or variant MCP calls unless those tools are present in the active host tool list.
Do not claim an MCP operation was used when the active host does not expose it.

Anti-Patterns

Claiming a Stitch screen-generation, screen-editing, or screen-retrieval MCP call succeeded when the active host does not expose that tool.
Uploading files, screenshots, HTML, markdown, or design assets to Stitch without user-approved destination and artifact details.
Reading, printing, storing, or committing Stitch API keys, MCP config secrets, cookies, or credential-bearing files.
Treating generated design or code as final without local render, syntax, or artifact verification.
Collapsing this workflow into a broader frontend/design skill when Stitch-specific files, project IDs, or design-system assets matter.

Verification Protocol

Before claiming this skill was applied successfully:

Pass/fail: Baton frontmatter has a page slug and concrete task body.
Pass/fail: SITE.md reflects sitemap, completed pages, and next backlog item.
Pass/fail: Generated or integrated pages were checked locally or unavailable generation is recorded.
Pass/fail: The loop leaves a next baton for the following session.
Pressure-test scenario: Repeat the workflow with Stitch MCP screen tools unavailable and confirm the fallback path remains honest and actionable.
Success metric: The user can identify the exact artifact, project/design-system target, and verification evidence without relying on unstated MCP behavior.

Related Skills

stitch-generate-design: Use when the task also needs this adjacent Stitch workflow.
stitch-design-md: Use when the task also needs this adjacent Stitch workflow.
stitch-extract-static-html: Use when the task also needs this adjacent Stitch workflow.
web-testing: Use when the task also needs this adjacent Stitch workflow.