diff --git a/packages/haddock3_catalog/README.md b/packages/haddock3_catalog/README.md
index fa6931a..244c58f 100644
--- a/packages/haddock3_catalog/README.md
+++ b/packages/haddock3_catalog/README.md
@@ -11,6 +11,8 @@ Run with
 # Reads modules from haddock3 in Python path
 ./generate_haddock3_catalog.py
 # Writes catalog files in public/catalog/ dir
+
+# TODO add command to check JSON schemas are valid.
 ```
 
 Translations from haddock3 -> i-VRESSE workflow builder:
diff --git a/packages/haddock3_catalog/generate_haddock3_catalog.py b/packages/haddock3_catalog/generate_haddock3_catalog.py
index 221bf1a..aa92dbd 100755
--- a/packages/haddock3_catalog/generate_haddock3_catalog.py
+++ b/packages/haddock3_catalog/generate_haddock3_catalog.py
@@ -331,6 +331,7 @@ def config2schema(config):
                     "type": "string",
                     "format": "chain"
                 }
+                prop['default'] = v['default']
             else:
                 raise ValueError(f"Don't know how to determine type of items of {v}")
         else: