Bug: Multiple ADK Artifacts render identical download links in Google Enterprise (Vertex AI) #4711
Description
Description
When an ADK ( 1.26.0) agent is deployed to Google Agentspace Enterprise (Vertex AI Agent Engine), a rendering issue occurs if two distinct tools call save_artifact sequentially within the same agent invocation (turn).
The Enterprise frontend correctly renders two separate download buttons with their respective icons and labels. However, both buttons trigger the download of the same file—specifically, the last artifact saved during that session.
Root Cause Analysis
The issue lies in how the Enterprise frontend resolves download links for each rendered button.
The ADK stores artifacts using two identifiers:
filename: The name of the file (e.g., processes.xlsx).
version: A version number incremented with each save_artifact call within the same session.
In the Enterprise environment, artifacts are stored in Google Cloud Storage (GCS) using a specific versioning schema. Unlike the local development environment (adk web / adk run)—which tracks filename directly—the Enterprise frontend appears to resolve download links by the session's latest version index at the time of message rendering, rather than mapping each button to its specific filename referenced in the tool response.
Consequently, all download buttons in a single turn point to the artifact with the highest version number.