Agentbricks Knowledge Assistant - Facing Issue with Agent Creation and Source Visibility

[Ajay-Pandey]

Hi Team,

I am facing an issue while creating a Knowledge Assistant in the Agent section. It was working fine earlier, and I had uploaded multiple PDF files (70K). However, it has now started behaving unexpectedly.

• I am not able to see any source data in the UI, although it is visible via the API.
• The agent is also not returning answers based on the source data.
• When I try to create a new agent, I receive the following error:

"Could not retrieve the agent.
There was an error retrieving the agent. If the problem persists, please contact support."

[Ashwin_DSA]

Hi @Ajay-Pandey,

From the snapshots, I would treat this as a possible UI/control-plane issue, especially if the source data is still visible through the API but not in the Knowledge Assistant UI.

A few things I would suggest checking first:

• Confirm the workspace meets the basic Knowledge Assistant requirements... such as ... Serverless compute, Unity Catalog, Model Serving access, a nonzero serverless usage policy budget, and a supported region (the public docs list these under Knowledge Assistant requirements). Docs
• Double-check the source format and file limits. For volume-based sources, the supported file types are txt, pdf, md, ppt/pptx, and doc/docx. The docs also note that files larger than 50 MB are skipped, and that PDF/DOC/DOCX/PPT/PPTX files with more than 500 pages are skipped as well. Docs
• If the source is an AI Search index instead of files, verify that the index uses a supported embedding model. The current public docs list databricks-gte-large-en, databricks-bge-large-en, and databricks-qwen3-embedding-0-6b. Docs
• If this is a file-based source, try a manual Sync. The docs mention that file-based knowledge sources need to be synced after updates, while index-based sources update automatically. Docs
• Give the agent enough time if it was recently created or updated. The public docs note that agent creation and source sync can take up to a few hours, and once the agent is ready, the right-side panel should display the synced knowledge sources. Docs
• Test the agent from the Build tab or from Playground and see whether it returns citations at all. The docs also mention using "View sources" to inspect the references the assistant is citing. Docs

If the API still returns the Knowledge Assistant and its knowledge sources, but the UI shows an empty Sources pane or displays "Could not retrieve the agent," I’d recommend opening a Databricks support case. That usually points more to a mismatch between the backend and the UI than to unsupported source files.

For the support ticket, it would help to include:

• Workspace URL, cloud, and region
• The Knowledge Assistant name and ID if available
• The exact error text
• Screenshots of the empty Sources UI and the retrieval error
• Whether the problem affects only one assistant or also newly created assistants
• The source type being used (volume, table, or AI Search index)
• Sample file types and approximate file sizes/page counts
• Whether manual Sync was attempted
• API output from the Knowledge Assistants endpoints, especially the assistant state and the list of knowledge sources

The public API reference for Knowledge Assistants is here if you want to compare UI behaviour with backend state: API reference

Hope this helps.

If this answer resolves your question, could you mark it as “Accept as Solution”? That helps other users quickly find the correct fix.