Microsoft Foundry Agents deployment issues

Error Message:

Response failed with code downstream_error: Unhandled workflow failure - #agent4 (InvokeAzureAgent) -> {"error":"Error invoking agent","agent":{"type":"agent_reference","name":"CapabilityAgent","version":"4"},"conversation_id":"","details":{"error":{"message":"No tool output found for remote function call ","type":"invalid_request_error","param":"input","code":null}}}. Workflow Setup (Tools & Configuration Only)

• I have a multi-agent workflow built in Microsoft Foundry and published to Microsoft Teams / Copilot using InvokeAzureAgent. The workflow consists of four sequential agents:
  1. Agent 1
     • Initially used: web_search_preview tool
     • Now: No tools configured
     • Output type: text (Markdown)
  2. Agent 2
     • No tools configured
     • Output type: text
  3. Agent 3
     • Sharepoint tools configured
     • Output type: text
  4. Agent 4 (final agent)
     • No tools configured
     • Output type: text
     • This is the only agent that sends output back to Teams
  All agents are configured with:
  • model: gpt-4.1
  • Text-only output
  • No structured/JSON output
  • No function calling enabled

  Issue Observed

  When running the published workflow from Teams / Copilot, execution fails with the following error:

    downstream_error: Unhandled workflow failure
  

  The error consistently appears at the Agent 4 invocation, even though:
  • Agent 4 has no tools
  • Agent 4 is text-only
  • No agents currently have any tools configured

  Key Observations

  • The same workflow runs successfully in Foundry Preview
  • The failure occurs only in Teams / Copilot
  • The error references a remote function call, even after all tools have been removed
  • This suggests a non-text message type (PortableValue / function-call frame) is still present in the message stream