Can't get mcp icons to work in cursor ide

Support Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Trying to setup a new mcp server I’m building using icons from the november protocol spec and can’t get the icon to actually show in cursor. I’ve verified on mcp inspector that the icon works on the mcp server and shows there.

There’s this thread from jan that got closed without an update. I did try just removing sizes from my icon info, but that didn’t help either. MCP Client: Icon.sizes incorrectly validated as string instead of array

Steps to Reproduce

Connect an mcp server that has icons in its server configuration

Operating System

MacOS

Version Information

2.6.12.

Does this stop you from using Cursor

No - Cursor works, but with this issue

3

Hey, thanks for the report. The previous issue with Icon.sizes validation (where it expected a string instead of an array) was fixed a while ago, and the SDK was updated.

That said, even with the fix, MCP server icons still might not render in the Cursor UI. To dig into this a bit more, could you share:

  1. Your MCP server icon configuration (the relevant JSON or config snippet showing how icons are defined)
  2. Any errors in the developer console (Help > Toggle Developer Tools > Console) when connecting the MCP server

This will help us figure out whether the icons are being accepted but just not displayed, or if there’s still a validation issue.

4

I haven’t been able to get any logs from the developer tools related to the connection.

icons: [

  {

src: 'data:image/svg+xml;base64,<base64-encoded-logo-svg>',

mimeType: 'image/svg+xml',

sizes: ['any'],

},

],

the server config isn’t anything special. while doing debugging it’s seeming like possibly the mcp client isn’t re-running the /initialize step ever where the icon actually gets loaded / injected but that’s just a guess

one other thing with this, it would be great if the team could add in the about cursor both the current mcp sdk version and the mcp protocol spec date / version!

5

Thanks for the config snippet and for checking the dev console.

Here’s what’s going on. The previous Icon.sizes validation bug where it rejected arrays was fixed in the SDK update. Since you’re not seeing any console errors, your icon config is probably being accepted fine.

But it looks like Cursor’s UI might not render custom MCP server icons yet, even if they’re correctly defined in the server config. That would explain why MCP Inspector shows the icon but Cursor doesn’t. Different clients have different support.

I’ve flagged this with the team. No ETA yet on when custom MCP server icons will show up in the UI, but your report helps us prioritize it.

Also, your idea to show the MCP SDK version and protocol spec version in About Cursor is a good one. I’ll pass it along.

8

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