Connect ChatGPT

ChatGPT takes Vessero in two places, and your plan decides which:

• ChatGPT on the web, at chatgpt.com on a computer: Business, Enterprise and Edu. On Business, only an admin or owner can add Vessero.
• The ChatGPT desktop app: every plan, Plus and Free too. The desktop app connects through Codex, which every plan includes.

ChatGPT connects by signing in to Vessero: it can't use an API key. In Connected apps, the same steps open one at a time for the place you pick, and the last one tells you when ChatGPT is in.

On the web

1. Pick where you use ChatGPT. Use the web on a Business, Enterprise or Edu workspace. Switch to the workspace first.
2. Add a custom MCP server. On chatgpt.com, open Plugins in the sidebar. Some accounts show Apps instead.
3. Select the plus button, then Add custom MCP server.
4. Enter the name Vessero.
5. Under Connection, enter https://vessero.com/mcp, exactly as it is here.
6. Set authentication to OAuth.
7. Tick I understand and want to continue, then select Create as a plugin.
8. Sign in to Vessero. When ChatGPT sends you to Vessero's page, sign in if it asks, then press Allow.
9. Back in ChatGPT, select Install plugin if it's shown, and Connect if it asks.
10. Pick Vessero with @. Start a new conversation, type @ in the message box and select Vessero.
11. Check it works. Ask: "Use Vessero to show my credit balance." It answers with your balance.

ChatGPT asks you before it makes anything with Vessero.

In the desktop app

1. Pick where you use ChatGPT. Use the desktop app on any plan, Plus and Free included.
2. Add a custom MCP server. In the ChatGPT desktop app, open Settings, then MCP servers.
3. Select Add server.
4. Enter the name vessero, choose Streamable HTTP and enter https://vessero.com/mcp.
5. Save it, then select Restart.
6. Sign in to Vessero. Select Authenticate next to vessero.
7. Vessero's page opens. Sign in if it asks, then press Allow.
8. Check it works. Start a Codex chat and type /mcp: vessero is listed.
9. Ask: "Use Vessero to show my credit balance." Approve the tool when it asks.

The desktop app shares this with Codex in your terminal and your editor. See Connect Codex.

Good to know

• Pro on the web lets a custom MCP server read only: Vessero can show your balance and your work there, but not make things.
• New tools. ChatGPT keeps a snapshot of Vessero's tools. When Vessero adds some, open it under Plugins and select Refresh. In a workspace, an admin refreshes them in the workspace settings.
• In a workspace, others can use Vessero once an admin or owner shares the plugin.
• On a phone, ChatGPT doesn't use custom MCP servers: they work on the web.

If it doesn't connect

• There's no Add custom MCP server. Your plan or role doesn't have it on the web. On Business, only an admin or owner can add one; on Enterprise, an admin can give you Create plugins with MCPs. On Plus or Free, use the desktop app.
• "Disabled by admin" or "Admin approval required". Ask your workspace admin.
• It's connected, but ChatGPT doesn't use it. Start a new chat and pick Vessero with @.
• The desktop app doesn't connect. Under Settings › MCP servers, check the address reads exactly https://vessero.com/mcp, then select Restart.