mctxdocs
For subscribers

Getting Started

You subscribed to an App — here's how to install it and make your first request.

Need help? Connect help.mctx.ai for instant answers.

You just subscribed. Here is what that means and what to do next.

You're Subscribed — Now What?

Your subscription gives you access to the App's tools through any compatible AI client. The App runs on mctx infrastructure — you do not host anything or manage any services.

Terminology: In this guide, we call these "servers" (the technical term). On the marketplace and in billing, you'll see them called "AI Apps" — it's the same thing, just a different name for subscribers vs. developers.

What you have access to:

  • The App's full set of tools, callable from your AI client
  • The specific version listed on your subscription card
  • Usage-based billing — you pay only for requests you make, nothing if you make none

Your next step is to install the App in your AI client. This takes about two minutes.

Install in Your AI Client

Go to your subscriptions page and expand the Installation Instructions section on the App card. You will find the exact commands with your App's slug and version pre-filled.

If you need to construct the URL manually, mctx Apps support two URL options:

Versionless (recommended) — always connects to the latest deployed version:

https://{slug}.mctx.ai

Pinned to a specific version — stays on a fixed version until you update the URL:

https://{slug}.mctx.ai/v{version}

For example: https://weather-api.mctx.ai or https://weather-api.mctx.ai/v1.0.0

Use the versionless URL unless you have a reason to stay on a specific version. It means you get improvements automatically without updating your configuration.

Claude Desktop

  1. Open Claude Desktop
  2. Click "Customize" (toolbox icon) in the left pane → click "Connectors"
  3. Click "+" (top right) → click "Add custom connector"
  4. Fill in the App name and the URL below, then click "Add" and authenticate

Server URL:

https://{slug}.mctx.ai

Replace {slug} with the App's slug from your subscription card. To pin to a specific version, use https://{slug}.mctx.ai/v1.0.0 with the version shown on your card.

Claude Code (CLI)

Run this command in your terminal:

claude mcp add --transport http {slug} https://{slug}.mctx.ai

Replace {slug} with the App's slug. To pin to a specific version instead, use https://{slug}.mctx.ai/v1.0.0 with the version shown on your subscription card.

Verify it was added:

claude mcp list

You should see the App listed.

ChatGPT

Requires ChatGPT Plus, Pro, Business, Enterprise, or Education plan. Setup must be done in the ChatGPT web app at chatgpt.com — the macOS app does not support this.

  1. Go to chatgpt.com and sign in
  2. Open Settings → Apps → Advanced settings
  3. Toggle "Developer mode" on
  4. Click "Create app" on the Advanced settings line
  5. Fill in the server name and the App URL below
  6. Set Authentication to "OAuth"
  7. Check "I understand and want to continue"
  8. Click "Create" — ChatGPT will complete the OAuth flow automatically

App URL:

https://{slug}.mctx.ai

Replace {slug} with the App's slug from your subscription card.

OpenClaw

Run this command in your terminal:

openclaw mcp add --transport streamable-http {slug} https://{slug}.mctx.ai

Replace {slug} with the App's slug. To pin to a specific version, use https://{slug}.mctx.ai/v1.0.0 with the version shown on your subscription card.

You can also install via the mctx marketplace — see Install via OpenClaw for the full guide.

Codex

Run this command in your terminal:

codex mcp add {slug} --url https://{slug}.mctx.ai

To pin to a specific version, use --url https://{slug}.mctx.ai/v1.0.0 instead.

Cursor

Open Cursor's MCP settings (Settings → MCP) and add the App under mcpServers:

{
  "mcpServers": {
    "{slug}": {
      "url": "https://{slug}.mctx.ai"
    }
  }
}

Replace {slug} with the App's slug. To pin to a specific version instead, use "url": "https://{slug}.mctx.ai/v1.0.0" with the version from your subscription card. Restart Cursor after saving.

VS Code

Ensure the GitHub Copilot extension is installed in VS Code.

Option 1 — Command Palette:

  1. Open the Command Palette (Cmd+Shift+P on macOS, Ctrl+Shift+P on Windows/Linux)
  2. Run "MCP: Add Server…"
  3. Select "HTTP (HTTP or Server-Sent Events)"
  4. Enter the App URL: https://{slug}.mctx.ai
  5. Choose a name for the App

Option 2 — Config file:

Add to .vscode/mcp.json in your workspace:

{
  "servers": {
    "{slug}": {
      "type": "http",
      "url": "https://{slug}.mctx.ai"
    }
  }
}

Replace {slug} with the App's slug from your subscription card.

Windsurf

  1. Open Windsurf
  2. Open the MCP configuration file at ~/.codeium/windsurf/mcp_config.json
  3. Add the App config block below
  4. Restart Windsurf to connect
{
  "mcpServers": {
    "{slug}": {
      "serverUrl": "https://{slug}.mctx.ai"
    }
  }
}

Replace {slug} with the App's slug from your subscription card.

Zed

Option 1 — Settings file:

  1. Open Zed
  2. Open Settings (Cmd+, on macOS)
  3. Add the App to the context_servers section:
{
  "context_servers": {
    "{slug}": {
      "settings": {
        "url": "https://{slug}.mctx.ai"
      }
    }
  }
}

Option 2 — Agent Panel:

Click "Add Custom Server" in the Agent Panel settings gear menu.

Replace {slug} with the App's slug from your subscription card.

Other MCP Clients

Any MCP-compatible client that supports automatic OAuth sign-in works with mctx. The pattern is the same:

  1. Add an HTTP-based App entry
  2. Set the URL to https://{slug}.mctx.ai (or https://{slug}.mctx.ai/v{version} to pin a version)
  3. Leave authentication blank — your client handles it automatically

Consult your client's documentation for where to add App configuration.

Make Your First Request

The first time you use the App, your AI client will open a browser window and ask you to sign in with your mctx account. This is the OAuth consent flow. It happens once per client.

After you sign in:

  1. The client stores the token securely
  2. You return to your AI client
  3. The App's tools become available

From that point forward, authentication is handled automatically. You do not need to sign in again unless your token expires or you reinstall the client.

Try it: Ask your AI to use the App directly. For example, if you installed a weather App:

"Use the weather App to get the current conditions in Chicago"

Your AI client will call the App's tool and return the result.

Manage Your Subscription

Visit app.mctx.ai/subscriptions to:

  • See all your active subscriptions
  • View installation instructions for each App
  • Check usage for the current billing period
  • Cancel a subscription

Canceling stops future billing immediately. Access ends within minutes of cancellation.

Troubleshooting

The OAuth window didn't open

Some clients suppress popups. Try:

  1. Check if your browser blocked a popup — look for a notification in the address bar
  2. Restart your AI client and try the request again
  3. If your client has a "reconnect" or "sign in" option for Apps, use that

Tools aren't appearing

After completing OAuth, some clients need a moment to load the tool list. Try:

  1. Wait a few seconds and try again
  2. Restart your AI client
  3. Confirm the App URL in your configuration is correct — either https://{slug}.mctx.ai (versionless) or https://{slug}.mctx.ai/v{version} (pinned)

Connection errors or "Server not found"

Check that:

  1. Your subscription is active at app.mctx.ai/subscriptions
  2. The URL in your configuration matches the slug exactly (case-sensitive)
  3. If you are using a pinned version URL, confirm the version exists — check your subscription card for available versions

Getting a 402 error

A 402 means your identity was confirmed but no active subscription was found. This usually means:

  • You're signed in to a different mctx account than the one you subscribed with
  • Your subscription was canceled or payment failed

Check app.mctx.ai/subscriptions to confirm your subscription is active and that you are signed in to the right account.

Authentication keeps failing

Try re-authenticating:

  1. Remove the App from your AI client configuration
  2. Add it back
  3. When prompted, sign in to the same mctx account you subscribed with

If the problem persists, see How Authentication Works for a technical explanation of what the client is doing and where things can go wrong.

Next Steps

See something wrong? Report it or suggest an improvement — your feedback helps make these docs better.

Your Vanity Link

Every mctx server gets a custom vanity link. Use it everywhere you promote your server.

Install via Claude Code & Claude Desktop

Install any mctx App via the Claude Code plugin marketplace or via the Connectors panel in Claude Desktop.

On this page

You're Subscribed — Now What?Install in Your AI ClientClaude DesktopClaude Code (CLI)ChatGPTOpenClawCodexCursorVS CodeWindsurfZedOther MCP ClientsMake Your First RequestManage Your SubscriptionTroubleshootingThe OAuth window didn't openTools aren't appearingConnection errors or "Server not found"Getting a 402 errorAuthentication keeps failingNext Steps