The MCP Server Guide Anyone Can Understand
By Miguel Torrez, founder of Genial Agency
You will know what an API and an MCP server are, check which actions a Claude connector actually offers (using Gmail as the example), and know what to do when the action you need is missing.
What you need
A Claude account with at least one connected app (I use Gmail)
For the API route: access to the app's settings to create an API key
Claude Code, Codex or ChatGPT Work if you plan to use an API key
Step by step
Understand what an API is
Think of an API as every action you can take inside an application, listed out one by one. It is also how two apps talk to each other. My example: when you post an Instagram story and also get the choice to post it on Facebook, that works through an API connection.
See how an MCP server connects AI to that API
An MCP server takes the API of an application (its list of actions) and builds a simpler way for AI applications to connect to it. When Claude talks to your Gmail or calendar, it goes through an MCP server.
Remember that each MCP server holds only some actions
The developer who builds an MCP server decides which actions go in. One server might include read, search, create and update but leave out permissions or billing. That is why one application can have several MCP servers, each with a different set of actions.
Recognize when the AI hits a missing action
If you ask the AI to do something the MCP server does not include (for example, export everything from your app), it hits a wall. It will tell you it cannot do that through the MCP, even though you can do it in the application yourself. That message means the action is missing, not that the AI failed.
Open your connectors in Claude
In Claude, go to connections and click Manage Connectors. Click a connector you already use. I pick Gmail and confirm I am connected to my Gmail account.
Read the list of actions
Look at the actions the connector exposes, grouped by what they do. In my Gmail connector there are 5 actions to read things from email and 11 actions to create things. Scan the list for the specific action you need before you ask Claude to do it.
Spot what is not there
Check for gaps. The Gmail connector has no action for sending an email, so Claude cannot send Gmail messages. This is because the MCP server Google built leaves out that action, even though the Gmail API has it. Official connectors change over time, so check again later.
Connect through the API directly if you hit a wall
Go into your account on the app, open settings and create a new API key. Treat it as a free pass to your account: think twice about which keys you create and where you use them.
Use the key with an AI that supports API keys
Use the API key with Claude Code, Codex or ChatGPT Work. You cannot use API keys with standard Claude or Claude Cowork, so pick the right tool before you start.
Watch out for
Assuming the AI is incapable when it says it cannot do something: often the action is simply not in that MCP server.
Expecting Claude to send Gmail messages: Google's Gmail connector does not include a send action.
Handling API keys carelessly: a key is a free pass to your account.
Trying to use an API key in standard Claude or Claude Cowork, which cannot use them.
Watch next
7:03The Two Agentic AI Tools You Need to LearnInstall Claude Code or Codex, the agents that can use an API key when a connector falls short.
8:39Connect Claude to Your Social Media with ZernioAdd a custom connector to Claude and choose exactly which actions it is allowed to take.
6:13Stop Wasting Hours: Analyze Any Video with AISee a real example: hand an API key to your agent and put it to work.
