Registering the Bareun connector in ChatGPT

If you turn on Developer mode in ChatGPT, you can add any remote MCP server directly as a custom connector. There is no review or registration process. You just enter the address. Once connected, ChatGPT calls Bareun during a conversation to perform Korean morphological analysis and spell checking.

What you need

A Bareun API key: For issuing keys and checking usage, see Using the cloud.
An endpoint address: For Bareun Cloud, it is https://api.bareun.ai:443/mcp. If you installed the Korean spell checker yourself, use that server's https address, reachable from outside, followed by /mcp. MCP is provided only by Bareun builds that include the Korean spell checker. Installations that include only morphological analysis do not have /mcp.

Developer mode differs by plan and version

Developer mode is an account-level setting, and the menu names and locations change slightly depending on the ChatGPT version. On Business and Enterprise, a workspace admin must allow it first before it appears in your personal settings. The range of write tools you can use also differs by plan, so if you do not see the menu, check whether your plan supports it.

How to register

Do this in a web browser. You do not enter the key on the settings screen. You enter it once in the login window that opens when you connect.

Turn on Developer mode under Settings → Apps & Connectors → Advanced.
Go back to the connector list and choose Create.
Enter the values below.
- Name: Bareun (or any name you like)
- Description: Korean morphological analysis and spelling and grammar correction (or whatever you like)
- MCP server URL: https://api.bareun.ai:443/mcp
- Authentication: OAuth
When you Connect the connector you created, a login window opens. Enter your Bareun API key there to log in.
When the connection succeeds, Bareun's five tools (analyze_syntax, analyze_syntax_raw, tokenize, list_pos_tags, correct_grammar) are registered.

The value you enter in the login window = your Bareun API key

Bareun identifies users by API key. So the value you enter in the connector login window is your Bareun API key. Once you log in, the credentials are stored, and you do not need to enter them again from then on.

If your screen lets you enter headers directly

If your version supports entering request headers, you can authenticate with a header instead of OAuth. Put your Bareun API key in the api-key header and you get the same result.

Verifying the connection

If you see Bareun and its tool list on the connector settings screen, it is connected. You can turn tools on and off one by one, and when the server changes, use Refresh to reload the list.
If you make a request in the chat window such as "Correct this sentence with Bareun," ChatGPT calls Bareun.

Troubleshooting

Can't find the Developer mode menu? Check whether your account plan supports it, and if you are on Business or Enterprise, whether your workspace admin has allowed it.
Getting a permission error (401)? Check that the value you entered in the login window is a valid Bareun API key. If you disconnect the connector and log in again, it reconnects cleanly.
Can't connect, or don't see the tools? Check that the address ends with /mcp. For an on-premises server, it must be an https address reachable from outside. ChatGPT cannot reach an internal network or a localhost address on a personal PC.
No spelling correction tool? MCP is provided only by Bareun builds that include the Korean spell checker.

Frequently asked questions

Q. Do I need a review or approval to add Bareun MCP to ChatGPT?

No. If you turn on Developer mode, you can add the Bareun server address directly as a custom connector. There is no separate registration or approval process.

Enter your Bareun API key. Bareun identifies users by API key, so the value you enter in the login window is the API key. Once you log in, the credentials are stored.

Q. Can I connect to a Bareun installed on my personal PC?

Not directly. ChatGPT connects only to https addresses reachable from the internet, so it cannot reach a localhost address or an internal network address. To use an on-premises server, prepare a domain and certificate reachable from outside, or use a client that runs locally (Claude Code, VS Code, Cursor, and so on).