Blob.display_name not preserved when loading binary artifacts from FileArtifactService / GcsArtifactService

[eliasecchig]

Description

When you save an artifact whose Part.inline_data.display_name is set (e.g., a
user-facing filename), the value is lost on load_artifact for
FileArtifactService and GcsArtifactService. InMemoryArtifactService
preserves it. Same shape as #3157 (.text lost on load), fixed by #5155 for
the text path.

Downstream, the genai → A2A converter at
part_converter.py:218
reads name=part.inline_data.display_name, so FilePart.file.name becomes
None and clients fall back to a generic attachment.<ext> label.

To Reproduce

import asyncio
import tempfile

from google.adk.artifacts import FileArtifactService, InMemoryArtifactService
from google.genai import types


async def main() -> None:
 for label, svc in [
 ("in-memory", InMemoryArtifactService()),
 ("file", FileArtifactService(base_path=tempfile.mkdtemp())),
 ]:
 await svc.save_artifact(
 app_name="app", user_id="u", session_id="s", filename="report.png",
 artifact=types.Part(
 inline_data=types.Blob(
 mime_type="image/png",
 data=b"\x89PNG\r\n\x1a\n...",
 display_name="report.png",
 )
 ),
 )
 loaded = await svc.load_artifact(
 app_name="app", user_id="u", session_id="s", filename="report.png"
 )
 print(f"{label:10s} display_name={loaded.inline_data.display_name!r}")


asyncio.run(main())

Output:

in-memory display_name='report.png'
file display_name=None

Expected

display_name round-trips through save → load for all artifact services.

Observed

• FileArtifactService._load_artifact
  (line 494)
  rebuilds the Part as
  types.Part(inline_data=types.Blob(mime_type=mime_type, data=data)).
  display_name is also not written to metadata.json on save, so it's
  genuinely lost on disk.
• GcsArtifactService._load_artifact
  (line 271)
  uses Part.from_bytes(...), which sets display_name=None.

Environment

• google-adk==2.1.0
• Python 3.12.13, macOS (also reproduces on linux)

Question

Is this expected behavior, or a bug?

Related

• Artifact stored as text is not retrieved as text #3157 — .text not preserved on load. Same shape.
• fix: restore .text attribute when loading text artifacts from GCS #5155 — fix for Artifact stored as text is not retrieved as text #3157 (open, approved). The display_name fix would live
  in the same place.

[llalitkumarrr]

Hello @eliasecchig ,

We reproduced this issue and observed the same behavior.

To resolve this, could you please modify line 494 in FileArtifactService._load_artifact to return types.Part(inline_data=types.Blob(mime_type=mime_type, data=data,display_name=filename)) and check if this resolves the issue? Kindly let us know if this works for you.

[adk-bot]

This issue has been automatically marked as stale because it has not had recent activity for 7 days after a maintainer requested clarification. It will be closed if no further activity occurs within 7 days.

[adk-bot]

This has been automatically closed because it has been marked as stale for over 7 days.