MCP Context Provider (@MCP token) always shows "No Results"

[xNefas]

As shown by the screenshot, despite having an active MCP server, I am unable to use it with the @MCP token.
Is this a bug? If so, is there any way around it by defining a custom MCP context provider that uses stdio?

This is my current config for my MCP server.

mcpServers:
  - name: brave-web-search
    command: npx
    args:
      - "-y"
      - "@brave/brave-search-mcp-server"
      - "--transport"
      - "stdio"
    env:
      BRAVE_API_KEY: ***************************-***
      BRAVE_MCP_TRANSPORT: stdio

Any and all help is appreciated, I just want to reference my MCP server with certain arguments sometimes (smaller context, specific function, etc.)