diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 56010eef..93444d21 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -1,6 +1,6 @@
-name: Run install, format, lint, build, and test on every push or pull request
+name: Run install, format, lint, build, and test on every push
 
-on: [push, pull_request]
+on: [push]
 
 jobs:
   build:
@@ -38,3 +38,17 @@ jobs:
       - name: Run tests with coverage
         working-directory: ./clients/web
         run: npm run test:coverage
+
+      - name: Cache Playwright browsers
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/ms-playwright
+          key: playwright-${{ runner.os }}-${{ hashFiles('clients/web/package-lock.json') }}
+
+      - name: Install Playwright browsers
+        working-directory: ./clients/web
+        run: npx playwright install --with-deps chromium
+
+      - name: Run Storybook play-function tests
+        working-directory: ./clients/web
+        run: npm run test:storybook
diff --git a/AGENTS.md b/AGENTS.md
index 71f9493e..aeb445a4 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -77,6 +77,7 @@ All work should be driven by items on the project board.
 
 ### Lint-fixed, Formatted code
 - ALWAYS do `npm run validate` before pushing any changes, this runs the various lint, build, format checks, etc.
+- Also run `npm run test:storybook` before pushing — it executes every story's `play` function in headless Chromium via `@vitest/browser-playwright` (~10s). CI runs this as a separate step after the unit/lint/build checks; failures block merge. It is kept out of `validate` because it needs the Playwright browser binary and is much slower than the unit suite.
 
 ### Typescript instructions
 - Use TypeScript for all new code
diff --git a/clients/web/package.json b/clients/web/package.json
index cae64f53..0684d21c 100644
--- a/clients/web/package.json
+++ b/clients/web/package.json
@@ -16,7 +16,8 @@
     "test": "vitest run --project=unit",
     "test:watch": "vitest --project=unit",
     "test:coverage": "vitest run --project=unit --coverage",
-    "test:storybook": "vitest run --project=storybook"
+    "test:storybook": "vitest run --project=storybook",
+    "test:storybook:watch": "vitest --project=storybook"
   },
   "dependencies": {
     "@emotion/react": "^11.14.0",
diff --git a/package.json b/package.json
index 2ad3d018..ceb784e6 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,8 @@
   "scripts": {
     "validate": "cd ./clients/web/ && npm run validate",
     "test": "cd ./clients/web/ && npm run test",
-    "test:coverage": "cd ./clients/web/ && npm run test:coverage"
+    "test:coverage": "cd ./clients/web/ && npm run test:coverage",
+    "test:storybook": "cd ./clients/web/ && npm run test:storybook"
   },
   "dependencies": {
     "@modelcontextprotocol/ext-apps": "^1.7.1",