Why can't I find Developer Mode in ChatGPT?

Developer Mode lives under Settings then Apps then Advanced Settings, and it needs a paid plan — Plus, Pro, Business, Enterprise, or Edu, not Free. It is also web only, so you won't see it in the ChatGPT mobile apps. On Business, Enterprise, or Edu, an admin first has to enable custom MCP in Workspace Settings before the toggle appears for you.

Lookups work in ChatGPT but saves don't. Why?

That is ChatGPT's plan-level write gate. OpenAI documents full MCP support, including tools that save and update, for Business, Enterprise, and Edu workspaces. On Plus and Pro, expect lookups to work and treat write tools as limited. ChatGPT may also ask you to confirm a write the first time it runs.

Is the orange border around ChatGPT a problem?

No. The orange border just means Developer Mode is active, which is required for custom MCP apps. It isn't a jailbreak or a warning, and it is expected while you have a custom app connected.

How to Add a Custom MCP Server to ChatGPT

How do I add a custom MCP server to ChatGPT?

Enable Developer Mode under Settings → Apps → Advanced Settings, then Create App, paste the server's URL, leave Authentication set to OAuth, scan the tools, and create. Two constraints decide whether this is even possible for you: custom MCP apps need a paid plan and are web only — they don't run in the ChatGPT mobile apps.

What plan you need, and what it gets you

As of August 2026, custom MCP apps are available on Plus, Pro, Business, Enterprise, and Edu — not Free.

The plan also determines what the connection can do, which is the part people discover late:

OpenAI documents full MCP — tools that can save and update — for Business, Enterprise, and Edu workspaces.
Pro is described as connecting MCP servers with read and fetch permissions in developer mode.
On Plus and Pro, expect lookups to work and treat write tools as limited.

So a connection where lookups work and saves do not run is usually not a broken integration — on Plus and Pro, write tools are documented as limited. ChatGPT may also ask you to confirm a write the first time it runs, which is a separate cause worth ruling out.

On Business, Enterprise, and Edu, an admin first enables custom MCP under Workspace Settings → Permissions & Roles → Connected Data, and each admin toggles Developer Mode for themselves.

Enabling Developer Mode

Log in to ChatGPT on the web
Click your profile name or icon in the lower-left
Click Settings
Go to Apps — older versions label this "Apps & Connectors" or "Connectors"; OpenAI renamed connectors to apps in December 2025
Click Advanced Settings
Toggle Developer Mode on

If that path doesn't match what you see: OpenAI's developer documentation describes the toggle under Settings → Security and login → Developer mode, with custom apps created from chatgpt.com/plugins. Both paths have been documented during 2026 and the labels vary by account and build. Try the other one rather than concluding the feature is missing.

Creating the app

With Developer Mode on, go to Settings → Apps → Advanced Settings and click Create App. Fill in:

Icon — upload one to make the app easy to spot
Name — what you'll select in the chat menu
Description — optional
MCP Server URL — the server's endpoint
Authentication — leave the default set to OAuth
Check the "I understand" acknowledgment for custom MCP server risk
Click Scan Tools — current versions scan the server's tool list before creation. With OAuth, complete the authorization prompt first, then let the scan finish.
Click Create — the app appears with a "Dev" label. Workspace admins see it under a Drafts tab until published.

Authorization

After creating the app, ChatGPT prompts you to authenticate: a browser window opens with the server's authorization page, you log in if prompted, review the permissions, and approve. You are redirected back to ChatGPT with the connection active.

Using it in a conversation

Custom apps are not automatically on in every chat:

Open a new chat
Click the + button in the chat input area
Click More
Select your app

You can also @-mention the app by name in a prompt to bring it in. To refresh context, start a new chat.

About that orange border

The orange border around the ChatGPT interface while Developer Mode is active is normal and expected. It is not a jailbreak, not a warning, and not a sign anything is misconfigured. Developer Mode is a beta feature for building and connecting custom MCP tools, and the border is simply its indicator.

What usually goes wrong

Problem	Fix
Developer Mode toggle not visible	Requires a paid plan (Plus and up); on Business/Enterprise/Edu an admin may need to enable custom MCP first. Confirm you are on ChatGPT web — custom apps aren't available on mobile.
Saves don't run, lookups work	The plan-level write gate. Full MCP write support is documented for Business, Enterprise, and Edu workspaces.
"Create App" not available	Developer Mode isn't toggled on in Advanced Settings.
Authorization doesn't complete	Clear browser cache and retry.
App not showing in chat menu	Click + → More to find it.
Context doesn't load	Start a new conversation with the app enabled.

A worked example

With a real server — Tempreon, a hosted MCP server that carries your context across every AI tool you connect:

https://api.tempreon.com/functions/v1/tempreon-mcp/mcp

Create the app with that URL, Authentication set to OAuth, and approve in the browser. The point of connecting a portable memory server here specifically is cross-provider reach: knowledge stored in a Claude session is available in ChatGPT and vice versa, with no manual syncing.

The account-holder walkthrough, with screenshots of each dialog, is in the ChatGPT setup doc.