diff --git a/CHANGES.md b/CHANGES.md
index d08f679..6ff3ff0 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -9,6 +9,7 @@ releases are available on [PyPI](https://pypi.org/project/pytask-r) and
 
 - {pull}`33` deprecates INI configurations and aligns the plugin with pytask v0.3.
 - {pull}`34` adds mypy, ruff and refurb.
+- {pull}`35` publishes types.
 
 ## 0.2.0 - 2022-04-16
 
diff --git a/MANIFEST.in b/MANIFEST.in
index ebba16e..438b3ea 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -8,3 +8,5 @@ exclude tox.ini
 
 include LICENSE
 include README.md
+
+recursive-include src py.typed
diff --git a/src/pytask_r/config.py b/src/pytask_r/config.py
index 15260db..f107589 100644
--- a/src/pytask_r/config.py
+++ b/src/pytask_r/config.py
@@ -21,7 +21,7 @@ def pytask_parse_config(config: dict[str, Any]) -> None:
     config["r_options"] = _parse_value_or_whitespace_option(config.get("r_options"))
 
 
-def _parse_value_or_whitespace_option(value: str | None) -> None | str | list[str]:
+def _parse_value_or_whitespace_option(value: Any) -> list[str] | None:
     """Parse option which can hold a single value or values separated by new lines."""
     if value is None:
         return None
diff --git a/src/pytask_r/py.typed b/src/pytask_r/py.typed
new file mode 100644
index 0000000..e69de29
diff --git a/src/pytask_r/shared.py b/src/pytask_r/shared.py
index 6a9f6ca..b3ae17f 100644
--- a/src/pytask_r/shared.py
+++ b/src/pytask_r/shared.py
@@ -9,7 +9,8 @@
 
 
 def r(
-    script: str | Path = None,
+    *,
+    script: str | Path,
     options: str | Iterable[str] | None = None,
     serializer: str | Callable[..., str] | str | None = None,
     suffix: str | None = None,
@@ -23,7 +24,7 @@ def r(
 
     Parameters
     ----------
-    script : Union[str, Path]
+    script : str | Path
         The path to the R script which is executed.
     options : str | Iterable[str]
         One or multiple command line options passed to Rscript.