ChatGPT & Claude (MCP)
Connect Any App to ChatGPT and Claude
ChatGPT and Claude can both connect to the software you use, but once you try it, it is harder than it sounds. Some apps connect right away, some look impossible, and some you cannot get to work. This walkthrough covers all three situations in order. If the app is already in Claude's connector directory or ChatGPT's Plugins list, you search for it, press plus, and log in. If it is not listed, check whether the app has an MCP server, which is how an AI assistant talks to another application: search the app's name plus MCP, copy the server URL, and add it as a custom connector in Claude or a custom plugin in ChatGPT. ChatGPT hides the plus button for custom plugins until developer mode is turned on under Settings, then Security and login, which is where most people get stuck. And if the app has no MCP server at all, that is not the end of it. If the app has an API you can reach as a customer, add it in Carly under Connect an API with its base URL and authentication type, and ChatGPT or Claude can then use that app through Carly. The authentication choices look technical, but in both ChatGPT and Carly you can trial and error them: pick one, and if it is wrong you are told and can switch.
Step by step
- 01
Check the ChatGPT and Claude marketplaces first
In Claude, press the plus, then Connectors, then Manage connectors, and open Discover. Search for your app, press plus, and it walks you through the login. In ChatGPT, open Plugins on the left-hand side for the same kind of prebuilt list.
- 02
Find the app's MCP server URL
If your app is not listed, look for an MCP server. MCP stands for model context protocol, a way for your AI assistant to talk to another application. Search the app's name plus "MCP" and copy the server URL from its page. Some apps also give you instructions you can paste straight to your agent.
- 03
Add it to Claude as a custom connector
Back in Claude's connector settings, press Add in the top right to add a custom connector. Name it and paste the MCP URL. Claude pre-selects what it detects from the server, so you can just press Add, then Connect, then Allow on the consent page.
- 04
Turn on developer mode in ChatGPT
No plus sign on ChatGPT's Plugins page? Click your profile, open Settings, go to Security and login, and turn on developer mode at the bottom. Go back to Plugins and the plus button is there.
- 05
Add it to ChatGPT as a custom plugin
Press the plus, name the plugin, and paste the MCP URL. Then choose how it authenticates. You do not need to know the answer in advance: if you pick the wrong one, ChatGPT tells you and you can change it. Press Create, then Allow on the consent page.
- 06
No MCP server? Look for the app's API
Search the app's name plus "API" and find its API docs. If you are a customer who can get an API key or login for that service, you can still connect it to ChatGPT and Claude.
- 07
Connect the API in Carly
Open the integrations page in Carly and go to Connect an API. Name it and paste the API base URL, which is usually at the very top of the docs and looks like api.yourapp.com. For authentication, pick username and password, bearer token, or API key. Not sure which? Try each one, then save.
- 08
Use the app from ChatGPT or Claude
With the Carly plugin in ChatGPT or the Carly connector in Claude, ask for the app by name. In the video, Granola meeting notes are connected through Carly, and ChatGPT or Claude finds them from there.
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