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Issue with Custom M365 Copilot Agent Adaptive Cards When Launched Directly from Microsoft 365 Copilot

Arshad Siraj Magdum 0 Reputation points
2026-04-02T06:25:05.5633333+00:00

We have developed a custom Copilot Agent using the Microsoft 365 Agent SDK in C#, and the agent has been successfully published on the Microsoft Marketplace.

Environment Details

  • Agent type: Custom Copilot Agent (M365 Agent SDK – C#)
  • Deployment: Published via Microsoft Marketplace
  • Client setup: Different Microsoft 365 tenant (cross-tenant usage)
  • Adaptive Cards version: 1.5
  • UI surface: Microsoft 365 Copilot (Copilot Chat)

Issue Description

In the client tenant, we are observing the following behavior:

  • The agent is automatically available in Microsoft 365 Copilot without being explicitly added from the Microsoft Marketplace.
  • When the agent is launched directly from Microsoft 365 Copilot, Adaptive Cards do not render initially.
  • After refreshing the browser page and using the agent again, Adaptive Cards render correctly, and the agent behaves as expected.
  • When the same agent is explicitly added from the Microsoft Marketplace and then used in Microsoft 365 Copilot, Adaptive Cards render correctly from the first interaction, without requiring a refresh.

Expected Behavior

  • Adaptive Cards (v1.5) should render consistently when the agent is launched directly from Microsoft 365 Copilot, without requiring a page refresh.

Actual Behavior

  • Adaptive Cards fail to render on the first load when the agent is accessed directly via Copilot, but work correctly after a manual refresh or when the agent is added via Microsoft Marketplace.

Questions

  1. Is this a known issue or limitation with Copilot agent loading in cross-tenant scenarios?
  2. Are there any recommended best practices to ensure Adaptive Cards render reliably without requiring a page refresh?

Any insights or guidance on ensuring consistent Adaptive Card rendering across all Copilot entry points would be greatly appreciated.

Thank you.

Microsoft Copilot | Microsoft 365 Copilot | Development
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  1. Sayali-MSFT 5,281 Reputation points Microsoft External Staff Moderator
    2026-04-03T08:46:55.4233333+00:00

    Hello Arshad Siraj Magdum,
    When a Marketplace-published agent is launched directly from the Microsoft 365 Copilot discovery pane in another tenant, it is only temporarily provisioned, not fully installed. During this first-run initialization, authentication, consent, token services, and host capability negotiation are still being set up.

    As a result, plain text responses work, but Adaptive Cards fail to render because the Copilot host cannot yet attach the renderer context. After a refresh—or once the agent is explicitly added from the Marketplace—the installation context completes, and Adaptive Cards render normally.

    Recommended mitigation: avoid sending Adaptive Cards on the first interaction. Use a warm-up text message first, then send Adaptive Cards on the second turn or after initialization completes.
    Reference Document-
    1.https://dotnet.territoriali.olinfo.it/en-us/microsoft-365/copilot/extensibility/api-plugin-authentication
    2.https://dotnet.territoriali.olinfo.it/en-us/microsoft-copilot-studio/authoring-ask-with-adaptive-card
    3.https://techcommunity.microsoft.com/blog/iis-support-blog/how-to-add-an-adaptive-card-in-microsoft-365-agent-sdk/4472022

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