Make custom URL schemes (slack://, vscode://) clickable in agent chat

Feature request for product/service

Chat

Describe the request

Agent replies often reference Slack threads. A browser link opens the web client, but the Slack desktop deeplink is what actually lands in the app. It looks like this:

slack://channel?team=TEAMID&id=CHANNELID&message=1787661978.418539&host=slack.com

That link works when pasted into Slack itself, but in Cursor agent chat it never becomes a live link. I tried every variant I could think of:

  • markdown link with the scheme as the URL
  • HTML anchor with href set to the scheme
  • angle-bracket autolink
  • ampersand-encoded query string
  • channel-only form with no message timestamp

In all cases clicking does nothing at all: no navigation, no error, no “open external app?” prompt. Regular https links in the same reply are clickable and work fine, so it looks like chat only wires http/https and silently drops anything else.

The OS handles the scheme correctly. Running open "slack://channel?..." in a terminal jumps straight to the right Slack thread, so the URL is valid and the app is registered as the handler.

Request: render registered custom URL schemes as clickable links in agent chat. An allowlist, or a one-time “open in external app?” confirmation, would both be fine from a safety point of view. This goes well beyond Slack, the same problem hits vscode://, cursor://, jetbrains://, notion:// and zoommtg:// deeplinks.

Current workaround is copy-pasting the deeplink into a terminal or the URL bar, which defeats the point of the agent surfacing it in the first place.

Environment: Cursor on macOS (darwin 25.6), Slack desktop installed, Slack enterprise grid workspace.

Operating System (if it applies)

MacOS