diff --git a/rust-bindings/src/model/profile.rs b/rust-bindings/src/model/profile.rs
index a369dc7..5946e9d 100644
--- a/rust-bindings/src/model/profile.rs
+++ b/rust-bindings/src/model/profile.rs
@@ -184,6 +184,7 @@ pub(crate) enum PyModelExtension {
     REDACTED_ENV_VARS = 1,
     FEATURE_BUNDLE_1 = 2,
     EXPR = 3,
+    WRAP_ACTIONS = 4,
 }
 
 #[cfg_attr(feature = "stub-gen", gen_stub_pymethods)]
@@ -238,6 +239,7 @@ impl From<PyModelExtension> for ModelExtension {
             PyModelExtension::REDACTED_ENV_VARS => ModelExtension::RedactedEnvVars,
             PyModelExtension::FEATURE_BUNDLE_1 => ModelExtension::FeatureBundle1,
             PyModelExtension::EXPR => ModelExtension::Expr,
+            PyModelExtension::WRAP_ACTIONS => ModelExtension::WrapActions,
         }
     }
 }
@@ -249,6 +251,20 @@ impl From<ModelExtension> for PyModelExtension {
             ModelExtension::RedactedEnvVars => PyModelExtension::REDACTED_ENV_VARS,
             ModelExtension::FeatureBundle1 => PyModelExtension::FEATURE_BUNDLE_1,
             ModelExtension::Expr => PyModelExtension::EXPR,
+            ModelExtension::WrapActions => PyModelExtension::WRAP_ACTIONS,
+            // `ModelExtension` is `#[non_exhaustive]`, so downstream
+            // crates cannot write an exhaustive match. This arm is
+            // mandatory, and the compiler will not warn when the Rust
+            // crate gains a variant that has no arm above. The fallback
+            // therefore MISREPRESENTS any such variant as `EXPR`.
+            //
+            // A new upstream variant requires three edits: a new
+            // `PyModelExtension` member, an arm here, and an arm in
+            // `From<PyModelExtension> for ModelExtension`. The guard
+            // against forgetting is
+            // `test/openjd/model_v1/test_version_enums.py::TestModelExtension`,
+            // which fails when this enum drifts from
+            // `openjd.model.v2023_09.ExtensionName`.
             #[allow(unreachable_patterns)]
             _ => PyModelExtension::EXPR,
         }
diff --git a/src/openjd/_openjd_rs.pyi b/src/openjd/_openjd_rs.pyi
index 48c7354..36947fd 100644
--- a/src/openjd/_openjd_rs.pyi
+++ b/src/openjd/_openjd_rs.pyi
@@ -3138,6 +3138,7 @@ class ModelExtension(enum.Enum):
     REDACTED_ENV_VARS = ...
     FEATURE_BUNDLE_1 = ...
     EXPR = ...
+    WRAP_ACTIONS = ...
 
     @property
     def name(self) -> builtins.str:
diff --git a/test/openjd/model_v1/test_pickle.py b/test/openjd/model_v1/test_pickle.py
index 4c77274..3c85309 100644
--- a/test/openjd/model_v1/test_pickle.py
+++ b/test/openjd/model_v1/test_pickle.py
@@ -52,6 +52,7 @@
         "openjd._openjd_rs.ModelExtension.REDACTED_ENV_VARS",
         "openjd._openjd_rs.ModelExtension.FEATURE_BUNDLE_1",
         "openjd._openjd_rs.ModelExtension.EXPR",
+        "openjd._openjd_rs.ModelExtension.WRAP_ACTIONS",
         "openjd._openjd_rs.TemplateSpecificationVersion.JOBTEMPLATE_v2023_09",
         "openjd._openjd_rs.TemplateSpecificationVersion.ENVIRONMENT_v2023_09",
     ],
diff --git a/test/openjd/model_v1/test_version_enums.py b/test/openjd/model_v1/test_version_enums.py
index bf31d32..945c641 100644
--- a/test/openjd/model_v1/test_version_enums.py
+++ b/test/openjd/model_v1/test_version_enums.py
@@ -3,6 +3,8 @@
 import pytest
 
 from openjd.model._v1 import TemplateSpecificationVersion, decode_job_template
+from openjd.model._v1.types import ModelExtension
+from openjd.model.v2023_09 import ExtensionName
 
 # All known variants. Add new ones here as the spec evolves; the test
 # ensures every variant is classified as exactly job-template OR
@@ -56,3 +58,48 @@ def test_template_specification_version_returned_from_decode(self) -> None:
         # like behaviour without being a str subclass).
         assert t.specification_version == "jobtemplate-2023-09"
         assert t.specification_version.value == "jobtemplate-2023-09"
+
+
+def _rust_extension_members() -> set[str]:
+    # `ModelExtension` is a PyO3 pyclass enum, not a real `enum.Enum`, so
+    # it is not iterable. Discover members by identity instead of relying
+    # on the enum protocol or a hardcoded list.
+    return {
+        name
+        for name in dir(ModelExtension)
+        if isinstance(getattr(ModelExtension, name), ModelExtension)
+    }
+
+
+class TestModelExtension:
+    """Drift guard for the `ModelExtension` PyO3 binding.
+
+    `openjd_model::types::ModelExtension` is `#[non_exhaustive]`, so
+    `From<ModelExtension> for PyModelExtension` must carry a catch-all
+    arm and the compiler cannot warn when the Rust crate gains a variant
+    the binding does not map. These tests are that warning.
+
+    Regression: `WRAP_ACTIONS` landed in the Rust crate six days after
+    the binding was written; the binding was never updated, so the
+    catch-all silently mapped it to `EXPR`. A profile built with
+    `WRAP_ACTIONS` therefore enabled `EXPR` instead, and templates using
+    `onWrapEnvEnter`/`onWrapTaskRun`/`onWrapEnvExit` were rejected with
+    an error that did not name the real cause.
+    """
+
+    def test_binding_members_match_python_extension_names(self) -> None:
+        # The binding enum and the Python model layer describe the same
+        # set of 2023-09 extensions. Divergence in either direction is a
+        # bug: a missing member means the catch-all aliases it to the
+        # wrong extension; an extra member means Python cannot name it.
+        assert _rust_extension_members() == {e.value for e in ExtensionName}
+
+    @pytest.mark.parametrize("name", [e.value for e in ExtensionName])
+    def test_name_round_trips_to_its_own_member(self, name: str) -> None:
+        # Catches aliasing directly, independent of member-set equality:
+        # every spec name must parse back to the member of the same name,
+        # never to a different extension.
+        parsed = ModelExtension.from_str(name)
+        assert parsed is not None, f"{name} is not recognized by the Rust binding"
+        assert parsed.name == name
+        assert parsed.as_str() == name