How to integrate GTmetrix MCP with Codex

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Introduction

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With GTmetrix MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or app, whichever you prefer.

Composio removes the Authentication handling completely from you. We handle the entire integration lifecycle, and all you need to do is just copy the URL below, authenticate inside Codex, and start using it.

Why use Composio?

Apart from a managed and hosted MCP server, you will get:

  • CodeAct: A dedicated workbench that allows GPT to write its code to handle complex tool chaining. Reduces to-and-fro with LLMs for frequent tool calling.
  • Large tool responses: Handle them to minimise context rot.
  • Dynamic just-in-time access to 20,000 tools across 870+ other Apps for cross-app workflows. It loads the tools you need, so GPTs aren't overwhelmed by tools you don't need.

How to install GTmetrix MCP in Codex

Codex CLI

Run the command in your terminal.

Terminal

This will auto-redirect you to the Rube authentication page.

Rube authentication redirect page

Once you're authenticated, you will be able to access the tools.

Verify the installation by running:

codex mcp list

If you otherwise prefer to use config.toml, add the following URL to it. You can get the bearer token from rube.app → Use Rube → MCP URL → Generate token

[projects."/home/user/composio"]
trust_level = "untrusted"

[mcp_servers.rube]
bearer_token_env_var = "your bearer token"
enabled = true
url = "https://rube.app/mcp"

Codex in VS Code

If you have installed Codex in VS Code.

Then: ⚙️ → MCP Settings → + Add servers → Streamable HTTP:

Add the Rube MCP URL: https://rube.app/mcp and the bearer token.

VS Code MCP Settings

To verify, click on the Open config.toml

Open config toml in Codex

Make sure it's there:

[mcp_servers.composio_rube]
bearer_token_env_var = "your bearer token"
enabled = true
url = "https://rube.app/mcp"

Codex App

Codex App follows the same approach as VS Code.

  1. Click ⚙️ on the bottom left → MCP Servers → + Add servers → Streamable HTTP:
Codex App MCP Settings
  1. Restart and verify if it's there in .codex/config.toml
[mcp_servers.composio_rube]
bearer_token_env_var = "your bearer token"
enabled = true
url = "https://rube.app/mcp"
  1. Save, restart the extension, and start working.

What is the GTmetrix MCP server, and what's possible with it?

The GTmetrix MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your GTmetrix account. It provides structured and secure access so your agent can perform GTmetrix operations on your behalf.

Supported Tools & Triggers

Tools
Delete PageTool to delete a specific page in GTmetrix.
Delete ReportTool to delete a GTmetrix report.
Get BrowsersTool to retrieve the list of available browsers for GTmetrix performance tests.
Get Location DetailsTool to retrieve location details from GTmetrix.
Get LocationsTool to retrieve the list of available GTmetrix test locations.
Get Page DetailsTool to retrieve page details from the user's GTmetrix account.
Get Page ReportsTool to retrieve the report list associated with a monitored page in GTmetrix.
Get PagesTool to retrieve the page list from your GTmetrix account.
Get ReportTool to retrieve a GTmetrix test report by its identifier.
Get Simulated DeviceTool to retrieve simulated device details.
Get Simulated DevicesTool to retrieve the list of simulated devices available in GTmetrix.
Get API Account StatusTool to retrieve the current API account state and remaining credits.
Get Test DetailsTool to retrieve test details for a specific GTMetrix test.
Get TestsTool to retrieve the test list from your GTmetrix account with pagination and filtering support.
Retest ReportTool to initiate a retest of a completed GTmetrix report with same parameters.
Start TestTool to start a new GTmetrix test for a specified URL.

Conclusion

You've successfully integrated GTmetrix with Codex using Composio's Rube MCP server. Now you can interact with GTmetrix directly from your terminal, VS Code, or the Codex App using natural language commands.

Key benefits of this setup:

  • Seamless integration across CLI, VS Code, and standalone app
  • Natural language commands for GTmetrix operations
  • Managed authentication through Composio's Rube
  • Access to 20,000+ tools across 870+ apps for cross-app workflows
  • CodeAct workbench for complex tool chaining

Next steps:

  • Try asking Codex to perform various GTmetrix operations
  • Explore cross-app workflows by connecting more toolkits
  • Build automation scripts that leverage Codex's AI capabilities

How to build GTmetrix MCP Agent with another framework

FAQ

What are the differences in Tool Router MCP and GTmetrix MCP?

With a standalone GTmetrix MCP server, the agents and LLMs can only access a fixed set of GTmetrix tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from GTmetrix and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with Codex?

Yes, you can. Codex fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right GTmetrix tools.

Can I manage the permissions and scopes for GTmetrix while using Tool Router?

Yes, absolutely. You can configure which GTmetrix scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your GTmetrix data and credentials are handled as safely as possible.

Used by agents from

Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai
Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai
Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai

Never worry about agent reliability

We handle tool reliability, observability, and security so you never have to second-guess an agent action.