diff --git a/.github/workflows/validate_tools_yaml.yml b/.github/workflows/validate_tools_yaml.yml
new file mode 100644
index 0000000..1cc88fe
--- /dev/null
+++ b/.github/workflows/validate_tools_yaml.yml
@@ -0,0 +1,22 @@
+name: validate tools yaml
+
+on:
+  pull_request:
+    paths: [ "tools.yml", "tools.schema.yaml", ".github/workflows/validate_tools_yaml.yml" ]
+  push:
+    paths: [ "tools.yml", "tools.schema.yaml", ".github/workflows/validate_tools_yaml.yml" ]
+  workflow_dispatch:
+
+permissions: read-all
+
+jobs:
+  lint-yaml:
+    runs-on: ubuntu-latest
+    steps:
+      - name: install yamale
+        run: pip install 'yamale>=5.2.1,<6'
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: lint tools yaml
+        run: yamale -s tools.schema.yaml tools.yml
+
diff --git a/tools.schema.yaml b/tools.schema.yaml
new file mode 100644
index 0000000..c0ee7b4
--- /dev/null
+++ b/tools.schema.yaml
@@ -0,0 +1,29 @@
+# yamale schema syntax: https://github.com/23andMe/Yamale#schema
+list(include('tool'))
+
+---
+
+tool:
+  name: str()
+  publisher: str()
+  description: str() # all after 250 chars is truncated
+  repoUrl: str(required=False)
+  websiteUrl: str(matches='^https?://.+')
+  categories: list(include('category'))
+
+# see tool-categories.yml
+category: >
+  enum(
+  'opensource',
+  'proprietary',
+  'build-integration',
+  'analysis',
+  'author',
+  'github-action',
+  'github-app',
+  'transform',
+  'library',
+  'signing-notary',
+  'distribute'
+  )
+