You used Stitch to explore screens, then flows broke after implementation.
You exported Stitch code but gates and role rules were never specced.
The name design in Stitch made you expect product behavior specs.
Figma MCP plus Stitch export still ships happy-path-only checkout.
Context
Stitch excels at fast visual exploration: prompt a screen, refine in the canvas, export assets or code. That is valuable early in a feature. The gap appears at merge time when your agent implements screens without a behavior contract. Stitch DESIGN.md carries tokens and layout intent; it does not carry hold lifecycles or partner submit gates. Lamina fills the behavior layer in the same repo your agent already edits.
Common situations
Concrete cases from AI-shipping workflows. Each shows what the alternative handles and where a behavior contract helps.
Exported checkout screen without hold rules
Situation
Stitch generated a polished checkout with timer UI. After export, the agent wired Confirm pay without enforcing email verification or hold expiry.
What Google Stitch does
Stitch produced the visual pattern for a hold banner and payment CTA. Export gives you components, not domain rules.
What Lamina adds
run.yaml defines legal transitions: hold active, email verified, policy agreed, then pay. Verify walks the guest path on the live build.
Takeaway
Export Stitch UI, spec behavior with Lamina before merge.
Exploring partner dashboard layouts
Situation
You used Stitch to compare sidebar vs stepped onboarding layouts before picking one for implementation.
What Google Stitch does
Stitch is the right tool for layout exploration and stakeholder review in the canvas.
What Lamina adds
After you pick a layout, /lamina-design defines which steps exist and when submit unlocks, independent of the visual pattern.
Takeaway
Stitch for exploration; Lamina for rules once you commit to a flow.
Static marketing site only
Situation
Stitch mockups for a launch page with no auth, checkout, or role-specific UI.
What Google Stitch does
Stitch alone is sufficient through export and implementation.
What Lamina adds
Not needed until the site gains interactive product behavior.
Takeaway
No behavior layer required for static pages.
Comparison
Lamina vs Google Stitch for AI developers
Dimension
Google Stitch
Lamina
Primary job
Generate high-fidelity UI from natural language
Spec states, flows, permissions
Layer in stack
Visual design canvas
Headless product design skill
Primary output
Screens, DESIGN.md, exportable code
run.yaml + implement.md
Writes app source?
Exports code you integrate
No
Behavior spec (states, flows, permissions)
Layout intent, not domain state machines
Permission matrices and legal transitions
Durable in-repo artifact
Design exports in project
.lamina/ contracts in git
Post-build verification
Visual iteration in Stitch canvas
/lamina-verify persona walks
Repo and stack fit
Export into your stack
Native to your repo and agent
Best when
Exploring layouts and visual direction fast
Shipping features with roles and gates
When you don't need Lamina
Static mockups or throwaway exploration
No production behavior rules needed
Compose with Lamina?
Explore UI in Stitch, export
Stitch → /lamina-design → implement → verify
Workflow
Lamina vs Google Stitch: recommended workflow
Step
Google Stitch
Lamina
1
Prompt screens in Stitch
Optional: parallel /lamina-design for behavior
2
Export to Figma or code
implement.md guides agent merge
3
Agent integrates visual components
Agent enforces contract rules
4
Visual QA in browser
/lamina-verify on staging
When to use which
Lamina vs Google Stitch: when to use each
Situation
Google Stitch
Lamina
Choosing between two dashboard layouts
Stitch exploration
After layout is chosen
Production booking with timers and gates
Stitch for UI chrome
Contract + verify required
Design system token draft
Stitch DESIGN.md
Not for tokens alone
Worked example
Inventory hold with countdown. Stitch can generate checkout UI with a countdown banner. Lamina specs hold timer rules, email verification gate, and cancellation consent before Confirm pay. HavenStay verify found pay enabled without verified email when the contract was skipped.
