diff --git a/api/pyproject.toml b/api/pyproject.toml
index 1dd926f24e..8dbedc7ea9 100644
--- a/api/pyproject.toml
+++ b/api/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "api"
-version = "0.56.0"
+version = "0.56.1"
 description = "Agenta API"
 authors = [
     { name = "Mahmoud Mabrouk", email = "mahmoud@agenta.ai" },
diff --git a/sdk/agenta/sdk/types.py b/sdk/agenta/sdk/types.py
index 25b79501c8..4440481bf5 100644
--- a/sdk/agenta/sdk/types.py
+++ b/sdk/agenta/sdk/types.py
@@ -21,13 +21,19 @@ def MCField(  # pylint: disable=invalid-name
     default: str,
     choices: Union[List[str], Dict[str, List[str]]],
 ) -> Field:
-    field = Field(default=default, description="ID of the model to use")
+    # Pydantic 2.12+ no longer allows post-creation mutation of field properties
     if isinstance(choices, dict):
-        field.json_schema_extra = {"choices": choices, "x-parameter": "grouped_choice"}
+        json_extra = {"choices": choices, "x-parameter": "grouped_choice"}
     elif isinstance(choices, list):
-        field.json_schema_extra = {"choices": choices, "x-parameter": "choice"}
-
-    return field
+        json_extra = {"choices": choices, "x-parameter": "choice"}
+    else:
+        json_extra = {}
+
+    return Field(
+        default=default,
+        description="ID of the model to use",
+        json_schema_extra=json_extra,
+    )
 
 
 class LLMTokenUsage(BaseModel):
diff --git a/sdk/pyproject.toml b/sdk/pyproject.toml
index c57d2b8b23..194fec6416 100644
--- a/sdk/pyproject.toml
+++ b/sdk/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "agenta"
-version = "0.56.0"
+version = "0.56.1"
 description = "The SDK for agenta is an open-source LLMOps platform."
 readme = "README.md"
 authors = [
diff --git a/web/oss/package.json b/web/oss/package.json
index 68c098b5c8..698a1aeea0 100644
--- a/web/oss/package.json
+++ b/web/oss/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@agenta/oss",
-    "version": "0.56.0",
+    "version": "0.56.1",
     "private": true,
     "engines": {
         "node": ">=18"
diff --git a/web/package.json b/web/package.json
index 4cec32420b..b79dcff972 100644
--- a/web/package.json
+++ b/web/package.json
@@ -1,6 +1,6 @@
 {
     "name": "agenta-web",
-    "version": "0.56.0",
+    "version": "0.56.1",
     "workspaces": [
         "ee",
         "oss",