diff --git a/docs/requirements.txt b/docs/requirements.txt
index c85e9f1..8b8bccd 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -2,6 +2,7 @@
 sphinx
 sphinx_rtd_theme
 nbsphinx
+sphinx_argparse
 
 # Also requires `brew install pandoc` on Mac
 pandoc
diff --git a/pyproject.toml b/pyproject.toml
index a222afe..eb66d0b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,26 +39,19 @@ classifiers = [
     "Operating System :: OS Independent",
 ]
 
-dependencies = [
-
-]
+dependencies = []
 
 [project.optional-dependencies]
 
 
 docs = [
     # For building the documentation
+    "sphinx", "sphinx_rtd_theme", "nbsphinx", "pandoc", "sphinx_argparse"
 ]
 
-all = [
-]
+all = []
 
-dev = [
-    "sphinx",
-    "sphinx_rtd_theme",
-    "nbsphinx",
-    "pandoc",
-]
+dev = []
 
 [project.urls]
 Homepage = "https://github.com/ecmwf/anemoi-models/"