Connect to Model Context Protocol (MCP) servers

MCP servers provide Gemini with additional tools and data sources. For example, by adding the Firebase MCP server, you can use natural language to explore your Cloud Firestore data while building or debugging your application.

Prerequisites

If required by the MCP server, ensure you have a working installation of Node.js and npm.

Choose a compatible MCP server

Firebase Studio has foundational support for MCP servers, but not all MCP servers are compatible. When choosing an MCP server, keep the following compatibility details in mind:

Supported:
- Standard input/output (stdio) or Server-Sent Events (SSE)/Streamable HTTP transport servers
- API key authentication using HTTP headers or environment variables
- Tools provided by MCP servers
Not supported:
- Servers that require a graphical user interface or a desktop session
- Prompts, sampling, or other resources provided by MCP servers

Add an MCP server

To add an MCP server, you need to create or edit its configuration file.

For your first server: Create the configuration file.
To add or adjust servers: Edit the server configuration.

Step 1: Create the configuration file

Interactive chat and Gemini CLI can both connect to MCP servers, but use different configuration files:

Interactive chat uses .idx/mcp.json.
Gemini CLI uses .gemini/settings.json.

Create one or both files using the following instructions.

Interactive chat

In Code view, create .idx/mcp.json using one of these methods:

Command Palette: Open the Command Palette (Shift+Ctrl+P), and use the Firebase Studio: Add MCP Server command.
Interactive chat: Click Customize Tools in interactive chat and select Add MCP server.
Explorer: From Explorer (Ctrl+Shift+E), right-click the .idx directory and select New file. Name the file mcp.json.

Gemini CLI

In Code view, create .gemini/settings.json:

In Explorer (Ctrl+Shift+E), check if the .gemini directory exists. If not, right-click the Explorer pane and select New folder. Name the folder .gemini.
Right-click the .gemini directory and select New file. Name the file settings.json.

For details about using MCP servers with Gemini CLI, review the full documentation.

Step 2: Edit the server configuration

Open the server configuration file.

Tip: To quickly open .idx/mcp.json, click Customize Tools in interactive chat and select Edit Config.

Add the server configuration to the content of the file. For example, to add the Firebase MCP server, enter:

{
  "mcpServers": {
   "firebase": {
     "command": "npx",
     "args": [
       "-y",
       "firebase-tools@latest",
       "experimental:mcp"
      ]
    }
  }
}

This configuration file instructs Gemini which MCP server you want it to use. This example shows a single server called firebase that will use the npx command to install and run firebase-tools@latest.

If your MCP server requires API key authentication, you can configure it in one of the following ways:

For remote HTTP MCP servers that require an API key in request headers, use the headers field. For example, to configure GitHub's MCP server:

{
  "mcpServers": {
    "github": {
      "url": "https://api.githubcopilot.com/mcp/",
      "headers": {
        "Authorization": "Bearer <ACCESS_TOKEN>"
      }
    }
  }
}

For local stdio MCP servers that require an API key in environment variables, use the env field. For example, to configure a local build of GitHub's MCP server:

{
  "mcpServers": {
    "github": {
      "command": "/path/to/github-mcp-server",
      "args": ["stdio"],
      "env": {
        "GITHUB_PERSONAL_ACCESS_TOKEN": "<ACCESS_TOKEN>"
      }
    }
  }
}

In the terminal (Shift+Ctrl+C), run any necessary commands to complete installation. For example, to use the Firebase MCP server, enter the following command to sign in to your account:
```
firebase login --no-localhost
```
Follow the instructions in the terminal to authorize the session. Some tools require a connected Firebase project. You can use the Firebase MCP server to create a project, or you can run the following command to initialize a Firebase project:
```
firebase init
```
This creates a firebase.json file in your root directory.

Use MCP tools

After installing the MCP server you want to use, the tools or data it provides are available in:

Gemini CLI
Interactive chat when using Agent mode and Agent (Auto-run) modes
the App Prototyping agent

For example, if you add the Firebase MCP server, you could ask Gemini to fetch the SDK config for the current project, retrieve data stored in Cloud Firestore and Realtime Database, help you set up Firebase services, and more.

In interactive chat, type / to see a list of available MCP prompts.

List of available MCP prompts

Check or adjust tools

You can manage which tools are active in interactive chat:

Click Customize Tools in interactive chat to see a list of all available tools from your configured MCP servers.
Use the checkboxes to enable or disable an entire server or individual tools.

List of available MCP tools

Troubleshoot MCP servers

If you encounter issues with an MCP server, use these steps to diagnose the problem.

Check the logs for errors

Open the Output panel (Shift+Ctrl+U).
In the drop-down menu, select Gemini.
Check for messages that begin with an [MCPManager] tag. These logs show which servers are configured, which tools were successfully added, and any error messages.

Rebuild the environment

If an MCP server fails to install or connect, try rebuilding your workspace:

Open the Command Palette (Shift+Ctrl+P).
Run the Firebase Studio: Rebuild Environment command.
After the workspace rebuilds, check if the MCP server connects.

If tools aren't being used

If the MCP server connects but Gemini doesn't use its tools:

Start a new chat session: This ensures Gemini picks up the latest tool configuration. Learn how to manage chat history.
Be specific in your prompt: If Gemini can accomplish the task without using an MCP tool, it might attempt a different method. If you want to use a specific tool, try naming the tool. For example: "Use firebase_get_sdk_config to get the SDK config for the current project."
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