diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 999c69e8..897cda4e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -90,8 +90,9 @@ jobs:
       - name: Build schema
         run: |
           python -m pip install --upgrade pip
-          pip install -e .[docs]
+          pip install -e .[docs] check-jsonschema
           python -m npe2.manifest.schema > _schema.json
+          check-jsonschema --check-metaschema _schema.json
       - name: Test rendering docs
         run: python _docs/render.py
         env:
@@ -122,8 +123,9 @@ jobs:
 
       - name: write schema
         run: |
-          pip install -e .
+          pip install -e . check-jsonschema
           python -m npe2.manifest.schema > schema.json
+          check-jsonschema --check-metaschema schema.json
 
       - name: Build and publish
         run: twine upload dist/*
diff --git a/src/npe2/manifest/contributions/_json_schema.py b/src/npe2/manifest/contributions/_json_schema.py
index 57564034..47a9f0fd 100644
--- a/src/npe2/manifest/contributions/_json_schema.py
+++ b/src/npe2/manifest/contributions/_json_schema.py
@@ -21,8 +21,8 @@
 ]
 
 JsonType = Literal["array", "boolean", "integer", "null", "number", "object", "string"]
-JsonTypeArray = conlist(JsonType, min_items=True, unique_items=True)
-StringArrayMin1 = conlist(str, unique_items=True, min_items=1)
+JsonTypeArray = conlist(JsonType, min_items=1, unique_items=True)
+StringArrayMin1 = conlist(str, min_items=1, unique_items=True)
 StringArray = conlist(str, unique_items=True)
 
 PY_NAME_TO_JSON_NAME = {