diff --git a/python/tests/unit/extensions/test_macros.py b/python/tests/unit/extensions/test_macros.py
index e1c2d89..2113082 100644
--- a/python/tests/unit/extensions/test_macros.py
+++ b/python/tests/unit/extensions/test_macros.py
@@ -106,8 +106,17 @@ class TestFilters:
 
 
 class TestMacroEnv:
-    def test_registers_macros_and_filters(self) -> None:
+    def test_conf_is_stored(self) -> None:
+        conf = {"site_name": "My Site", "docs_dir": "/docs"}
+        env = MacroEnv(conf=conf)
+        assert env.conf is conf
+
+    def test_conf_defaults_to_empty_dict(self) -> None:
         env = MacroEnv()
+        assert env.conf == {}
+
+    def test_registers_macros_and_filters(self) -> None:
+        env = MacroEnv(conf={})
 
         @env.macro
         def twice(value: int) -> int:
@@ -195,21 +204,42 @@ class TestLoadModule:
             "        return s.upper()\n",
             encoding="utf-8",
         )
-        variables, macros, filters = _load_module("main", tmp_path)
-        assert variables["site_name"] == "Demo"
-        assert macros["twice"](3) == 6
-        assert filters["shout"]("hi") == "HI"
+        env = MacroEnv(conf={})
+        _load_module(env, "main", tmp_path)
+        assert env.variables["site_name"] == "Demo"
+        assert env.macros["twice"](3) == 6
+        assert env.filters["shout"]("hi") == "HI"
 
     @pytest.mark.parametrize(
-        "module_name",
+        ("module_name", "file_rel_path"),
         [
-            pytest.param("../evil", id="path_traversal"),
-            pytest.param("foo/bar", id="forward_slash"),
-            pytest.param("foo\\\\bar", id="backslash"),
+            pytest.param("../evil", "../evil.py", id="path_traversal"),
+            pytest.param("foo/bar", "foo/bar.py", id="forward_slash"),
+            pytest.param("foo\\\\bar", "foo\\\\bar.py", id="backslash"),
         ],
     )
-    def test_rejects_invalid_names(self, module_name: str) -> None:
-        assert _load_module(module_name) == ({}, {}, {})
+    def test_rejects_invalid_names(
+        self,
+        module_name: str,
+        file_rel_path: str,
+        tmp_path: Path,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
+        define_env_source = (
+            "def define_env(env):\n"
+            "    env.variables['pwned'] = True\n"
+            "    env.macros['evil'] = lambda: None\n"
+            "    env.filters['bad'] = lambda x: x\n"
+        )
+        target = tmp_path / file_rel_path
+        target.parent.mkdir(parents=True, exist_ok=True)
+        target.write_text(define_env_source, encoding="utf-8")
+        monkeypatch.chdir(tmp_path)
+        env = MacroEnv(conf={})
+        _load_module(env, module_name)
+        assert env.variables == {}
+        assert env.macros == {}
+        assert env.filters == {}
 
 
 # ---------------------------------------------------------------------------
diff --git a/python/zensical/extensions/macros.py b/python/zensical/extensions/macros.py
index ba7dc60..706ab0c 100644
--- a/python/zensical/extensions/macros.py
+++ b/python/zensical/extensions/macros.py
@@ -148,7 +148,8 @@ See also the [Jinja2 documentation on builtin filters](https://jinja.palletsproj
 class MacroEnv:
     """Minimal env object for compatibility with MkDocs Macros."""
 
-    def __init__(self) -> None:
+    def __init__(self, conf: dict[str, Any] | None = None) -> None:
+        self.conf = conf if conf is not None else {}
         self.variables: VariablesType = {}
         self.macros: MacrosType = {}
         self.filters: FiltersType = {}
@@ -219,6 +220,7 @@ class MacrosPreprocessor(Preprocessor):
         page = context.page if context else None
         project_config = context.config if context else {}
         project_root = Path(project_config.get("root_dir", ".")).resolve()
+        macros_env = MacroEnv(conf=project_config)
 
         # Don't render if not enabled by default and no page-level override
         if (
@@ -260,21 +262,17 @@ class MacrosPreprocessor(Preprocessor):
         # Load module.
         # Relative path (without extension) or importable module name
         if self.config.module_name:
-            mod_vars, mod_macros, mod_filters = _load_module(
-                self.config.module_name,
-                project_root,
-            )
-            variables.update(mod_vars)
-            macros.update(mod_macros)
-            filters.update(mod_filters)
+            _load_module(macros_env, self.config.module_name, project_root)
 
         # Load pluglets (preinstalled modules)
         # Importable module names only
         for plug in self.config.modules:
-            plug_vars, plug_macros, plug_filters = _load_module(plug)
-            variables.update(plug_vars)
-            macros.update(plug_macros)
-            filters.update(plug_filters)
+            _load_module(macros_env, plug)
+
+        # Store declared variables, macros and filters.
+        variables.update(macros_env.variables)
+        macros.update(macros_env.macros)
+        filters.update(macros_env.filters)
 
         # Merge page metadata
         if page:
@@ -668,8 +666,8 @@ def _get_fake_table_readers() -> dict[str, Callable]:
 
 
 def _load_module(
-    module_name: str, project_root: Path | None = None
-) -> VariablesMacrosFiltersType:
+    env: MacroEnv, module_name: str, project_root: Path | None = None
+) -> None:
     """Load a module by name (e.g. 'main')."""
     if project_root:
         for candidate in [
@@ -687,24 +685,20 @@ def _load_module(
                 mod = importlib.util.module_from_spec(spec)
                 spec.loader.exec_module(mod)
                 if hasattr(mod, "define_env"):
-                    env = MacroEnv()
                     mod.define_env(env)
-                    return env.variables, env.macros, env.filters
+                    return
             break
 
     # Only try import for package-like names (no path separators or "..").
     if "/" in module_name or "\\" in module_name or ".." in module_name:
-        return {}, {}, {}
+        return
     try:
         mod = importlib.import_module(module_name)
     except ImportError:
         pass
     else:
         if hasattr(mod, "define_env"):
-            env = MacroEnv()
             mod.define_env(env)
-            return env.variables, env.macros, env.filters
-    return {}, {}, {}
 
 
 def _load_one_yaml(