[native-servers] Error in inputSchema function: [VALIDATION.INVALID_SCHEMA] must have a properties table in tables: Input schema

[nzlov]

if mcpservers.json has server. ex:

{
  "mcpServers": {
    "mysql": {
      "args": [
        "-url",
        "root:xxx@tcp(127.0.0.1:3306)/dev?charset=utf8mb4&parseTime=True&loc=Local"
      ],
      "command": "mysql"
    }
  }

open MCPHub

[ravitemer]

Sorry! What is the issue? How is this related to native servers? Please read Lua native MCP servers section in #40

[nzlov]

not use native servers.

{
        "ravitemer/mcphub.nvim",
        build = "npm install -g mcp-hub@latest", -- Installs required mcp-hub npm module
        branch = "native-servers",
        config = function()
          math.randomseed()
          local cfg = function()
            local cwd_config = vim.fn.getcwd() .. "/mcpservers.json"
            if vim.fn.filereadable(cwd_config) == 1 then
              return cwd_config
            else
              return vim.fn.expand("~/mcpservers.json")
            end
          end

          require("mcphub").setup({
            -- Required options
            --port = 30000, -- Port for MCP Hub server
            port = math.random(50000, 50100), -- Port for MCP Hub server

            config = cfg(), -- Prioritize config in current directory, fall back to home

            -- Optional options
            on_ready = function(hub)
              -- Called when hub is ready
            end,
            on_error = function(err)
              -- Called on errors
            end,
            shutdown_delay = 0, -- Wait 0ms before shutting down server after last client exits
            log = {
              level = vim.log.levels.WARN,
              to_file = false,
              file_path = nil,
              prefix = "MCPHub",
            },
          })
        end,
      }

[ravitemer]

 "mysql": {
      "args": [
        "-url",
        "root:xxx@tcp(127.0.0.1:3306)/dev?charset=utf8mb4&parseTime=True&loc=Local"
      ],
      "command": "mysql"
    }

mysql is not a MCP server right? We should only use programs that implement MCP protocol.

[ravitemer]

If that didn't work, can you go to http://localhost:30000/api/servers/mysql/info endpoint and share the result

[nzlov]

I've identified the cause of the issue. MySQL provides a tool called tables that returns descriptions of all tables in the database. This tool doesn't require any parameters.
Empty parameter tools should pass validation.

[ravitemer]

Then the new commit 76b1a04 should fix this

[nzlov]

now ok.

[ravitemer]

Great! Thank you for the find.