https://community.databricks.com/t5/generative-ai/databricks-app-cannot-authenticate-to-another-databricks-app-mcp/m-p/148260#M1633 <P>Hi Team,<BR /><BR />I am building an MCP client as a Databricks App that connects to an MCP server hosted on another Databricks App. The client works locally but fails when deployed due to OAuth consent redirect.<BR /><BR />Question: What is the recommended authentication approach for Databricks App-to-App communication?</P> Fri, 13 Feb 2026 07:26:37 GMT venkatved 2026-02-13T07:26:37Z https://community.databricks.com/t5/generative-ai/databricks-app-cannot-authenticate-to-another-databricks-app-mcp/m-p/148260#M1633 <P>Hi Team,<BR /><BR />I am building an MCP client as a Databricks App that connects to an MCP server hosted on another Databricks App. The client works locally but fails when deployed due to OAuth consent redirect.<BR /><BR />Question: What is the recommended authentication approach for Databricks App-to-App communication?</P> Fri, 13 Feb 2026 07:26:37 GMT https://community.databricks.com/t5/generative-ai/databricks-app-cannot-authenticate-to-another-databricks-app-mcp/m-p/148260#M1633 venkatved 2026-02-13T07:26:37Z https://community.databricks.com/t5/generative-ai/databricks-app-cannot-authenticate-to-another-databricks-app-mcp/m-p/149441#M1643 <P><STRONG>TLDR</STRONG>: For Databricks App-to-App communication, you should use the client app's automatically provisioned Service Principal rather than On-Behalf-Of (OBO) user authentication to avoid interactive OAuth consent redirects.<BR /><STRONG>Why Your Local Approach Fails in Deployment</STRONG> When relying on OBO user authentication, the platform requires the user to interactively grant consent via a browser redirect the first time they use the application. While this works when you are actively navigating an interface, an app-to-app background connection cannot process this interactive UI redirect, which causes the deployment to fail.<BR /><STRONG>Recommendation</STRONG>: Databricks Apps are natively designed with automatically managed Service Principals specifically built for secure app-to-app communication. Every time an app is created, it is automatically assigned a dedicated Service Principal.<BR /><STRONG>To fix your deployment</STRONG>:<BR />Use M2M Authentication: Configure your client Databricks App to authenticate to the server Databricks App using its dedicated Service Principal instead of passing through an OBO user token.<BR />Grant Access: Ensure you grant the client app's Service Principal the proper access permissions to hit the backend server app's API.</P> <P>Please accept the solution if my recommendation worked for you.</P> Fri, 27 Feb 2026 04:18:58 GMT https://community.databricks.com/t5/generative-ai/databricks-app-cannot-authenticate-to-another-databricks-app-mcp/m-p/149441#M1643 Lu_Wang_ENB_DBX 2026-02-27T04:18:58Z