MCP Client configuration to launch an MCP Server

The client configuration currently only allows setting "command" and "url" (or transport), but there’s no way to supply the MCP CLI’s --caps, --device, or other flags via an "args": […] array in the client’s JSON.

• As a result, I cannot enable the “tabs” capability (required for browser_tab_new to return usable tab IDs), nor pass any custom flags like from within the client.

• I also need to configure the SSE transport properly. Ideally the client could declare both the base URL and transport type, for example: {

"mcpServers": {

"command": "npx",

      "args": [

        "-y",

        "mcp-remote",

        "https://server.dev/sse",

        "--transport",

        "sse-only"

}

}

}. — For the config or may be for other reason I successfully use my MCP server tool in claude/cursor while when I use Agentic flow I get - the following mistake “ "output": "Failed to run tool.", "error": "string indices must be integers, not 'str'", "status": "error"“ when the call looks exactly the same