How a Cursor extension adds MCP tools and input blocks
Some Cursor can register an directly with Cursor. They can also copy an interface element from the extension and paste it into Cursor’s input box, where it appears as a link-like “” instead of ordinary text. Investigation suggests that MCP registration may use the lightly documented docs/extension-api API.
The special input rendering appears to rely on the clipboard format , which carries an instruction to use MCP tools along with the address of the current file. It remains unclear whether Cursor officially supports these features or whether extension discovered them by examining Cursor’s internal behavior.
Key points
- An extension can register an directly with Cursor.
- Copied interface elements can appear as a “” in Cursor’s input box.
- MCP registration may use the docs/extension-api API.
- The clipboard format appears to carry tool instructions and the current file address.
- Official support for these methods has not been confirmed.