Fix: Hyperlinks render as plain text in Copilot app (but work in the test pane in Copilot Studio)

My use case

SharePoint knowledge-retrieval agent built in Copilot Studio to answer employee questions from internal policy and guidance documents. These documents, in addition to text content, contain embedded hyperlinks to internal apps and resources (intranet pages, expense app, ticketing tools etc.). It was important for these links to be surfaced in the agent response so employees can directly follow the link - so they needed to be clickable hyperlinks, otherwise the answer was effectively incomplete. Note that I am not using specific topics/actions to create generative answers. I'm relying solely on instructions.

The problem

Hyperlinks from the source documents appeared as clickable links in Copilot Studio test pane, but when the same agent was published and accessed via the M365 Copilot app, the links were displayed as plain text - not clickable. My original instructions told the agent to include hyperlinks in content & I also verified that the hyperlinks in the source documents were all absolute URLs.

🙌 What changes finally worked

Keeping the original "include links" directive and adding a strict formatting rule that requires both Markdown formatting and an HTML <a> tag wrapper, with the URL preserved exactly. The final instruction lines I included:

• If hyperlinks are contained within the source content and related to the answer, ALWAYS include them in the response.
• ALWAYS format the link as full Markdown and preserve the URLs exactly within an HTML <a> tag.

What was the problem

Copilot Studio is a forgiving renderer. M365 Copilot app uses a stricter markdown rendered that can supress hyperlinks that don't come be default in the format it expects. Hence, including an explicit hyperlink formatting in the instructions helps.

I hope this helps someone and saves a few hours in troubleshooting the issue 😉