Where does the bug appear (feature/product)?
Cursor IDE
Describe the Bug
Description
The MCP client incorrectly expects serverInfo.icons[].sizes to be a string,
but the MCP specification defines it as an array of strings.
Error
{
“code”: “invalid_type”,
“expected”: “string”,
“received”: “array”,
“path”: [“serverInfo”, “icons”, 0, “sizes”]
}## Expected Behavior
Per the MCP specification,
sizes should accept an array like ["48x48", "96x96"].
Actual Behavior
Cursor’s client rejects arrays and only accepts a single string.
Similar Issue
Similar issue was resolved for Copilot-CLI: serverInfo.icons.sizes is wrongly expecting a string and fails MCP connection · Issue #486 · github/copilot-cli · GitHub.
Steps to Reproduce
Try to connect to an MCP that provides Icons with the sizes as an array (based on the spec).
Expected Behavior
Cursor’s client accepts MCP Icon size as arrays and tools load successfully.
Operating System
MacOS
Current Cursor Version (Menu → About Cursor → Copy)
Version: 2.1.46 (Universal)
VSCode Version: 1.105.1
Commit: ab326d0767c02fb9847b342c43ea58275c4b1680
Date: 2025-12-02T03:59:29.283Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 24.6.0
Does this stop you from using Cursor
No - Cursor works, but with this issue