# Connect ChatGPT to Tesselith

> Add Tesselith to ChatGPT as a custom MCP server and draft, queue and schedule social posts by chatting.

Canonical: https://tesselith.com/ai-agents/chatgpt

**Before you start:** You need a ChatGPT plan that allows custom MCP servers and a Tesselith workspace on Pro, Team or Agency (every new workspace starts with a 14-day Pro trial) with at least one channel connected. OpenAI's plan rules have changed several times; full read-and-write access is documented for Business, Enterprise and Edu workspaces, where an admin may need to allow custom apps first. ChatGPT signs in with OAuth only, so there's no API key to paste.

## Quick setup

```text
Name:            Tesselith
Connection:      Public endpoint
URL:             https://api.tesselith.com/mcp
Authentication:  OAuth
```

On some accounts the same screen is under Settings → Apps & Connectors → Advanced settings → Developer mode → Create.

## Step by step

### 1. Open Plugins and add a custom MCP server

In ChatGPT, open Plugins (chatgpt.com/plugins), click + and choose Add custom MCP server. If you don't see it, your account may still use the older flow under Settings → Apps & Connectors with Developer mode, or your workspace admin hasn't enabled custom apps.

### 2. Enter the Tesselith server

Name it Tesselith, choose a public endpoint, paste the URL and set Authentication to OAuth. Review OpenAI's warning about custom servers and confirm.

```text
https://api.tesselith.com/mcp
```

### 3. Create it and sign in

Click Create, review the tools ChatGPT discovered, and sign in when asked. A Tesselith window opens. Sign in, pick the workspace, untick anything you don't want the agent to do, and click Allow access.

### 4. Use it in a new chat

Start a new conversation, type @ and pick Tesselith (or enable it from the + menu on older accounts). ChatGPT asks before running write actions such as scheduling.

## Troubleshooting

- **No option to add a custom MCP server:** Your plan or workspace doesn't allow custom apps yet. On Business, Enterprise and Edu, ask an admin to enable them.
- **Tools are read-only:** Some plans limit custom servers to read and search. In workspaces, the admin also chooses which write actions are enabled.
- **New tools don't appear:** Open the server on the Plugins page, click Refresh, then start a new conversation.
- **You want to use an API key:** ChatGPT's custom servers support OAuth, not API keys. Use the sign-in flow; API keys work in Codex and the OpenAI API.

## Questions people ask

### Which ChatGPT plans can connect Tesselith?

Custom MCP servers need a paid plan. OpenAI documents full read-and-write access for Business, Enterprise and Edu; check your account's Plugins page for what yours allows.

### Does ChatGPT need my social media passwords?

No. ChatGPT acts through Tesselith with the permissions you approve. It never sees your network passwords or tokens.

### Can ChatGPT's deep research or agent mode use Tesselith?

Deep research uses custom servers for reading only, and OpenAI says agent mode doesn't use them, so schedule from a normal chat.

### How do I disconnect ChatGPT?

Remove the server from your Plugins page, and disconnect it in Tesselith under Settings → AI assistants to revoke access at once.

Docs: https://developers.openai.com/api/docs/guides/custom-mcp-server

---
Tesselith · https://tesselith.com · Full site index: https://tesselith.com/llms.txt