diff --git a/api/controllers/openapi/__init__.py b/api/controllers/openapi/__init__.py
index 4510042ef0..a117c18064 100644
--- a/api/controllers/openapi/__init__.py
+++ b/api/controllers/openapi/__init__.py
@@ -1,7 +1,7 @@
 from flask import Blueprint
 from flask_restx import Namespace
 
-from controllers.openapi._errors import ErrorBody, OpenApiErrorFormatter
+from controllers.openapi._errors import ErrorBody, OpenApiErrorCode, OpenApiErrorFormatter
 from libs.device_flow_security import attach_anti_framing
 from libs.external_api import ExternalApi
 
@@ -20,7 +20,7 @@ openapi_ns = Namespace("openapi", description="User-scoped operations", path="/"
 
 # Register response/query models BEFORE importing controller modules so that
 # @openapi_ns.response / @openapi_ns.expect decorators can resolve model names.
-from controllers.common.schema import register_response_schema_models, register_schema_models
+from controllers.common.schema import register_enum_models, register_response_schema_models, register_schema_models
 from controllers.openapi._models import (
     AccountPayload,
     AccountResponse,
@@ -127,6 +127,9 @@ register_response_schema_models(
     ServerVersionResponse,
     HealthResponse,
 )
+# Standalone definition for contract codegen; ErrorBody.code stays an open
+# string on the wire so old clients keep parsing future codes.
+register_enum_models(openapi_ns, OpenApiErrorCode)
 
 from . import (
     _meta,
diff --git a/api/tests/unit_tests/controllers/openapi/test_error_contract.py b/api/tests/unit_tests/controllers/openapi/test_error_contract.py
index 193c894a2d..12293de321 100644
--- a/api/tests/unit_tests/controllers/openapi/test_error_contract.py
+++ b/api/tests/unit_tests/controllers/openapi/test_error_contract.py
@@ -335,3 +335,15 @@ class TestErrorMatrix:
         assert wire["status"] == status
         assert wire["code"] in {c.value for c in OpenApiErrorCode}
         ErrorBody.model_validate(wire)
+
+
+class TestErrorCodeEnumRegistration:
+    def test_enum_registered_with_all_values(self):
+        from controllers.openapi import openapi_ns
+        from controllers.openapi._errors import OpenApiErrorCode
+
+        model = openapi_ns.models.get("OpenApiErrorCode")
+        assert model is not None
+        schema = model.__schema__
+        assert schema["type"] == "string"
+        assert set(schema["enum"]) == {member.value for member in OpenApiErrorCode}