fix(artifacts): accept dict-shaped artifacts in InMemoryArtifactService (#3495)

src/google/adk/agents/context.py

@@ -136,14 +136,15 @@ async def load_artifact(
   async def save_artifact(
       self,
       filename: str,
-      artifact: types.Part,
+      artifact: types.Part | dict[str, Any],
       custom_metadata: dict[str, Any] | None = None,
   ) -> int:
     """Saves an artifact and records it as delta for the current session.
 
     Args:
       filename: The filename of the artifact.
-      artifact: The artifact to save.
+      artifact: The artifact to save. Can be a types.Part object or a
+        dict-shaped (serialized) artifact.
       custom_metadata: Custom metadata to associate with the artifact.
 
     Returns:

src/google/adk/artifacts/base_artifact_service.py

@@ -63,14 +63,31 @@ class ArtifactVersion(BaseModel):
 class BaseArtifactService(ABC):
   """Abstract base class for artifact services."""
 
+  @staticmethod
+  def _convert_artifact_if_dict(
+      artifact: types.Part | dict[str, Any],
+  ) -> types.Part:
+    """Converts a dict-shaped artifact to types.Part if necessary.
+
+    Args:
+      artifact: The artifact to convert. Can be a types.Part or dict.
+
+    Returns:
+      A types.Part object. If input is already a Part, returns as-is.
+      If input is a dict, converts it to Part via model_validate.
+    """
+    if isinstance(artifact, dict):
+      return types.Part.model_validate(artifact)
+    return artifact
+
   @abstractmethod
   async def save_artifact(
       self,
       *,
       app_name: str,
       user_id: str,
       filename: str,
-      artifact: types.Part,
+      artifact: types.Part | dict[str, Any],
       session_id: Optional[str] = None,
       custom_metadata: Optional[dict[str, Any]] = None,
   ) -> int:
@@ -84,10 +101,11 @@ async def save_artifact(
       app_name: The app name.
       user_id: The user ID.
       filename: The filename of the artifact.
-      artifact: The artifact to save. If the artifact consists of `file_data`,
-        the artifact service assumes its content has been uploaded separately,
-        and this method will associate the `file_data` with the artifact if
-        necessary.
+      artifact: The artifact to save. Can be a types.Part object or a
+        dict-shaped (serialized) artifact that will be converted to types.Part.
+        If the artifact consists of `file_data`, the artifact service assumes
+        its content has been uploaded separately, and this method will associate
+        the `file_data` with the artifact if necessary.
       session_id: The session ID. If `None`, the artifact is user-scoped.
       custom_metadata: custom metadata to associate with the artifact.
 

src/google/adk/artifacts/file_artifact_service.py

@@ -314,7 +314,7 @@ async def save_artifact(
       app_name: str,
       user_id: str,
       filename: str,
-      artifact: types.Part,
+      artifact: types.Part | dict[str, Any],
       session_id: Optional[str] = None,
       custom_metadata: Optional[dict[str, Any]] = None,
   ) -> int:
@@ -326,6 +326,9 @@ async def save_artifact(
     computed scope root; absolute paths or inputs that traverse outside that
     root (for example ``"../../secret.txt"``) raise ``ValueError``.
     """
+    # Convert dict-shaped artifact to types.Part if necessary
+    artifact = self._convert_artifact_if_dict(artifact)
+
     return await asyncio.to_thread(
         self._save_artifact_sync,
         user_id,

src/google/adk/artifacts/gcs_artifact_service.py

@@ -61,10 +61,13 @@ async def save_artifact(
       app_name: str,
       user_id: str,
       filename: str,
-      artifact: types.Part,
+      artifact: types.Part | dict[str, Any],
       session_id: Optional[str] = None,
       custom_metadata: Optional[dict[str, Any]] = None,
   ) -> int:
+    # Convert dict-shaped artifact to types.Part if necessary
+    artifact = self._convert_artifact_if_dict(artifact)
+
     return await asyncio.to_thread(
         self._save_artifact,
         app_name,

src/google/adk/artifacts/in_memory_artifact_service.py

@@ -99,10 +99,13 @@ async def save_artifact(
       app_name: str,
       user_id: str,
       filename: str,
-      artifact: types.Part,
+      artifact: types.Part | dict[str, Any],
       session_id: Optional[str] = None,
       custom_metadata: Optional[dict[str, Any]] = None,
   ) -> int:
+    # Convert dict-shaped artifact to types.Part if necessary
+    artifact = self._convert_artifact_if_dict(artifact)
+
     path = self._artifact_path(app_name, user_id, filename, session_id)
     if path not in self.artifacts:
       self.artifacts[path] = []

src/google/adk/cli/adk_web_server.py

@@ -232,8 +232,8 @@ class SaveArtifactRequest(common.BaseModel):
   """Request payload for saving a new artifact."""
 
   filename: str = Field(description="Artifact filename.")
-  artifact: types.Part = Field(
-      description="Artifact payload encoded as google.genai.types.Part."
+  artifact: types.Part | dict[str, Any] = Field(
+      description="Artifact payload encoded as google.genai.types.Part or as a dict-shaped artifact."
   )
   custom_metadata: Optional[dict[str, Any]] = Field(
       default=None,

src/google/adk/tools/_forwarding_artifact_service.py

@@ -42,10 +42,12 @@ async def save_artifact(
       app_name: str,
       user_id: str,
       filename: str,
-      artifact: types.Part,
+      artifact: types.Part | dict[str, Any],
       session_id: Optional[str] = None,
       custom_metadata: Optional[dict[str, Any]] = None,
   ) -> int:
+    # Delegate to parent tool context, which will handle conversion in the
+    # concrete artifact service implementation.
     return await self.tool_context.save_artifact(
         filename=filename,
         artifact=artifact,

tests/unittests/artifacts/test_artifact_service.py

@@ -766,3 +766,102 @@ async def test_file_save_artifact_rejects_absolute_path_within_scope(tmp_path):
         filename=str(absolute_in_scope),
         artifact=part,
     )
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "service_type",
+    [
+        ArtifactServiceType.IN_MEMORY,
+        ArtifactServiceType.GCS,
+        ArtifactServiceType.FILE,
+    ],
+)
+async def test_save_load_dict_shaped_artifact(
+    service_type, artifact_service_factory
+):
+  """Tests saving and loading dict-shaped artifacts.
+
+  This tests the fix for accepting dict-shaped (serialized) artifacts
+  in the save_artifact method. Dict-shaped artifacts are commonly used
+  when artifacts are stored/retrieved from JSON or other serialization formats.
+  """
+  artifact_service = artifact_service_factory(service_type)
+  # Create a dict-shaped artifact by serializing a real Part instance
+  part = types.Part.from_bytes(data=b"test_data", mime_type="text/plain")
+  dict_artifact = part.model_dump(exclude_none=True)
+
+  app_name = "app0"
+  user_id = "user0"
+  session_id = "123"
+  filename = "dict_file.txt"
+
+  # Save the dict-shaped artifact
+  version = await artifact_service.save_artifact(
+      app_name=app_name,
+      user_id=user_id,
+      session_id=session_id,
+      filename=filename,
+      artifact=dict_artifact,
+  )
+  assert version == 0
+
+  # Load and verify the artifact
+  loaded = await artifact_service.load_artifact(
+      app_name=app_name,
+      user_id=user_id,
+      session_id=session_id,
+      filename=filename,
+  )
+  assert loaded is not None
+  assert loaded.inline_data is not None
+  assert loaded.inline_data.mime_type == "text/plain"
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "service_type",
+    [
+        ArtifactServiceType.IN_MEMORY,
+        ArtifactServiceType.GCS,
+        ArtifactServiceType.FILE,
+    ],
+)
+async def test_save_text_dict_shaped_artifact(
+    service_type, artifact_service_factory
+):
+  """Tests saving and loading dict-shaped artifacts with text content."""
+  artifact_service = artifact_service_factory(service_type)
+  # Create a dict-shaped artifact by serializing a real Part instance
+  part = types.Part(text="Hello, World!")
+  dict_artifact = part.model_dump(exclude_none=True)
+
+  app_name = "app0"
+  user_id = "user0"
+  session_id = "123"
+  filename = "text_file.txt"
+
+  # Save the dict-shaped artifact
+  await artifact_service.save_artifact(
+      app_name=app_name,
+      user_id=user_id,
+      session_id=session_id,
+      filename=filename,
+      artifact=dict_artifact,
+  )
+
+  # Load and verify the artifact
+  loaded = await artifact_service.load_artifact(
+      app_name=app_name,
+      user_id=user_id,
+      session_id=session_id,
+      filename=filename,
+  )
+  assert loaded is not None
+  # GCS/File services may return text as inline_data bytes; accept either form.
+  if loaded.text is not None:
+    assert loaded.text == "Hello, World!"
+  else:
+    assert (
+        loaded.inline_data is not None
+        and loaded.inline_data.data == b"Hello, World!"
+    )