MCPHub.nvim

A powerful Neovim plugin that integrates MCP (Model Context Protocol) servers into your workflow. Configure and manage MCP servers through a centralized config file while providing an intuitive UI for testing tools and resources. Perfect for LLM integration, offering both programmatic API access and interactive testing capabilities through the :MCPHub command.

MCP Hub Interface

demo.mp4

Using Codecompanion Chat plugin

chatdemo.mp4

💜 Sponsors

Thank you to the following people:

✨ Features

• Simple single-command interface (:MCPHub)
• Integrated Hub view for managing servers and tools
  • Dynamically enable/disable servers and tools to optimize token usage
  • Start/stop servers with persistent state
  • Enable/disable specific tools per server
  • State persists across restarts
• Parallel startup for improved performance
• Interactive UI for testing tools and resources
• Automatic server lifecycle management across multiple Neovim instances
• Smart shutdown handling with configurable delay
• Both sync and async operations supported
• Clean client registration/cleanup
• Comprehensive API for tool and resource access

📦 Installation

Using lazy.nvim:

{
    "ravitemer/mcphub.nvim",
    dependencies = {
        "nvim-lua/plenary.nvim",  -- Required for Job and HTTP requests
    },
    build = "npm install -g mcp-hub@latest", -- Installs required mcp-hub npm module
    config = function()
        require("mcphub").setup({
            -- Required options
            port = 3000,  -- Port for MCP Hub server
            config = vim.fn.expand("~/mcpservers.json"),  -- Absolute path to config file

            -- 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
}

Example configuration file:

{
  "mcpServers": {
    "fetch": {
      "command": "uvx",
      "args": ["mcp-server-fetch"]
    },
    "todoist": {
      "command": "npx",
      "args": ["-y", "@abhiz123/todoist-mcp-server"],
      "disabled": true,
      "env": {
        "TODOIST_API_TOKEN": "your-api-token-here"
      }
    }
  }
}

Requirements

• Neovim >= 0.8.0
• Node.js >= 18.0.0
• plenary.nvim
• mcp-hub (automatically installed via build command)

🚀 Usage

1. Open the MCPHub UI to manage servers, test tools and monitor status:

:MCPHub

You can:

• Start/stop servers directly from the Hub view
• Enable/disable specific tools for each server
• Test tools and resources interactively
• Monitor server status and logs

2. Use the hub instance in your code:

-- Get hub instance after setup
local mcphub = require("mcphub")

-- Option 1: Use on_ready callback
mcphub.setup({
    port = 3000,
    config = vim.fn.expand("~/mcpservers.json"),
    on_ready = function(hub)
        -- Hub is ready to use here
    end
})

-- Option 2: Get hub instance directly (might be nil if setup in progress)
local hub = mcphub.get_hub_instance()

-- Call a tool (sync)
local response, err = hub:call_tool("server-name", "tool-name", {
    param1 = "value1"
}, {
    return_text = true -- Parse response to LLM-suitable text
})

-- Call a tool (async)
hub:call_tool("server-name", "tool-name", {
    param1 = "value1"
}, {
    return_text = true,
    callback = function(response, err)
        -- Use response
    end
})

-- Access resource (sync)
local response, err = hub:access_resource("server-name", "resource://uri", {
    return_text = true
})

-- Get prompt helpers for system prompts
local prompts = hub:get_prompts({
    use_mcp_tool_example = [[<use_mcp_tool>
<server_name>weather-server</server_name>
<tool_name>get_forecast</tool_name>
<arguments>
{
  "city": "San Francisco",
  "days": 5
}
</arguments>
</use_mcp_tool>]],
    access_mcp_resource_example = [[<access_mcp_resource>
<server_name>weather-server</server_name>
<uri>weather://san-francisco/current</uri>
</access_mcp_resource>]]
})
-- prompts.active_servers: Lists currently active servers
-- prompts.use_mcp_tool: Instructions for tool usage with example
-- prompts.access_mcp_resource: Instructions for resource access with example

🔌 Extensions

MCPHub.nvim provides extensions that integrate with popular Neovim chat plugins. These extensions allow you to use MCP tools and resources directly within your chat interfaces.

Available Extensions

CodeCompanion Integration

Add MCP capabilities to CodeCompanion.

Add it as a dependency to load the plugin before codecompanion:

{
  "olimorris/codecompanion.nvim",
  dependencies = {
    "nvim-lua/plenary.nvim",
    "nvim-treesitter/nvim-treesitter",
    "ravitemer/mcphub.nvim"
  },
},

• Please note there are some breaking changes with codecompanion v13 in the way we configure tools.

  require("codecompanion").setup({
    strategies = {
        chat = {
            tools = {
                ["mcp"] = {
                    callback = require("mcphub.extensions.codecompanion"),
                    description = "Call tools and resources from the MCP Servers",
                    opts = {
                      -- user_approval = true,
                      requires_approval = true,
                    }
                }
            }
        }
    }
  })

See the extensions/ folder for more examples and implementation details.

Avante Integration

Add MCP capabilities to Avante.

⚠️ Tool Conflicts: Disable any built-in Avante tools that might conflict with enabled MCP servers to prevent duplicate functionality or unexpected behavior.

Setup

Add MCP capabilities to Avante by including the MCP tool in your setup:

require("avante").setup({
    -- other config
    -- The system_prompt type supports both a string and a function that returns a string. Using a function here allows dynamically updating the prompt with mcphub
    system_prompt = function()
        local hub = require("mcphub").get_hub_instance()
        return hub:get_active_servers_prompt()
    end,
    -- The custom_tools type supports both a list and a function that returns a list. Using a function here prevents requiring mcphub before it's loaded
    custom_tools = function()
        return {
            require("mcphub.extensions.avante").mcp_tool(),
        }
    end,
})

Note: You can also access the Express server directly at http://localhost:[port]/api

🔧 Troubleshooting

1. Environment Requirements

   • Ensure these are installed as they're required by most MCP servers:

     node --version    # Should be >= 18.0.0
     python --version  # Should be installed
     uvx --version    # Should be installed

   • Most server commands use npx or uvx - verify these work in your terminal

2. Port Issues

   • If you get EADDRINUSE error, kill the existing process:

     lsof -i :[port]  # Find process ID
     kill [pid]       # Kill the process

3. Configuration File

   • Ensure config path is absolute
   • Verify file contains valid JSON with mcpServers key
   • Check server-specific configuration requirements
   • Validate server command and args are correct for your system

4. MCP Server Issues

   • Validate server configurations using either:
     • MCP Inspector: GUI tool for verifying server operation
     • mcp-cli: Command-line tool for testing servers with config files
   • Check server logs in MCPHub UI (Logs view)
   • Test tools and resources individually to isolate issues

5. Need Help?

   • Create a Discussion for questions
   • Open an Issue for bugs

🔄 How It Works

MCPHub.nvim uses an Express server to manage MCP servers and handle client requests:

1. When setup() is called:

   • Checks for mcp-hub command installation
   • Verifies version compatibility
   • Starts mcp-hub with provided port and config file
   • Creates Express server at localhost:[port]

2. After successful setup:

   • Calls on_ready callback with hub instance
   • Hub instance provides REST API interface
   • UI updates in real-time via :MCPHub command

3. Express Server Features:

   • Manages MCP server configurations
   • Handles tool execution requests
   • Provides resource access
   • Multi-client support
   • Automatic cleanup

4. When Neovim instances close:

   • Unregister as clients
   • Last client triggers shutdown timer
   • Server waits shutdown_delay seconds before stopping
   • Timer cancels if new client connects

This architecture ensures:

• Consistent server management
• Real-time status monitoring
• Efficient resource usage
• Clean process handling
• Multiple client support

Architecture Flows

Server Lifecycle

sequenceDiagram
    participant N1 as First Neovim
    participant N2 as Other Neovims
    participant S as MCP Hub Server

    Note over N1,S: First Client Connection
    N1->>S: Check if Running
    activate S
    S-->>N1: Not Running
    N1->>S: start_hub()
    Note over S: Server Start
    S-->>N1: Ready Signal
    N1->>S: Register Client
    S-->>N1: Registration OK

    Note over N2,S: Other Clients
    N2->>S: Check if Running
    S-->>N2: Running
    N2->>S: Register Client
    S-->>N2: Registration OK

    Note over N1,S: Server stays active

    Note over N2,S: Client Disconnection
    N2->>S: Unregister Client
    S-->>N2: OK
    Note over S: Keep Running

    Note over N1,S: Last Client Exit
    N1->>S: Unregister Client
    S-->>N1: OK
    Note over S: Grace Period
    Note over S: Auto Shutdown
    deactivate S

Loading

Request flow

sequenceDiagram
    participant N as Neovim
    participant P as Plugin
    participant S as MCP Hub Server
    N->>P: start_hub()
    P->>S: Health Check
    alt Server Not Running
        P->>S: Start Server
        S-->>P: Ready Signal
    end
    P->>S: Register Client
    S-->>P: Registration OK
    N->>P: :MCPHub
    P->>S: Get Status
    S-->>P: Server Status
    P->>N: Display UI

Loading

Cleanup flow

flowchart LR
    A[VimLeavePre] -->|Trigger| B[Stop Hub]
    B -->|If Ready| C[Unregister Client]
    C -->|Last Client| D[Server Auto-shutdown]
    C -->|Other Clients| E[Server Continues]
    B --> F[Clear State]
    F --> G[Ready = false]
    F --> H[Owner = false]

Loading

API Flow

sequenceDiagram
    participant C as Chat Plugin
    participant H as Hub Instance
    participant S as MCP Server
    C->>H: call_tool()
    H->>H: Check Ready
    alt Not Ready
        H-->>C: Error: Not Ready
    end
    H->>S: POST /tools
    S-->>H: Tool Result
    H-->>C: Return Result
    Note over C,S: Similar flow for resources

    C->>H: access_resource()
    H->>H: Check Ready
    H->>S: POST /resources
    S-->>H: Resource Data
    H-->>C: Return Data

Loading

🚧 Future Enhancements

Currently planning these features:

• Workflow integration with CodeCompanion for enhanced code assistance
• Enhanced help view with comprehensive documentation
• Community marketplace for sharing and discovering MCP servers
• Add custom descriptions for each MCP server through the UI
• Support server-specific configuration through the interface

👏 Acknowledgements

Thanks to:

• nui.nvim for inspiring our text highlighting utilities