# Connect ChatGPT to ToolMesh via Developer Mode

> Wire ChatGPT to a ToolMesh MCP endpoint via OpenAI Developer Mode. Documents the connector dialog, OAuth login, and tool families exposed once connected.

Canonical: https://www.toolmesh.io/en/setup-openai/

ChatGPT supports MCP servers, but only **remote HTTPS servers** and only through **Developer Mode**. This guide walks through connecting ChatGPT to your ToolMesh instance.

## Requirements

- A **Plus, Pro, Business, Enterprise, or Education** plan (Free plan has no MCP support)
- ToolMesh accessible via a **public HTTPS URL** (ChatGPT cannot connect to `http://` or `localhost`)
- For local development, use [ngrok](https://ngrok.com) or [Cloudflare Tunnel](https://developers.cloudflare.com/cloudflare-one/connections/connect-networks/) to expose your ToolMesh instance

## Step-by-step setup

### 1. Enable Developer Mode

Open **Settings > Apps & Connectors > Advanced settings** and toggle **Developer Mode** on.

Note: Developer Mode **disables Memory** for conversations that use MCP tools.

### 2. Create the ToolMesh connector

Return to the **Apps & Connectors** settings page. Click the **Create** button (only visible after enabling Developer Mode) and fill in:

| Field | Value |
|-------|-------|
| **Name** | ToolMesh |
| **Description** | Secure execution layer for infrastructure tools |
| **MCP Server URL** | `https://toolmesh.example.com/mcp` |
| **Authentication** | OAuth or No Authentication |

Check **I trust this application** and click **Create**. If the connection succeeds, ChatGPT displays a list of available ToolMesh tools.

### 3. Complete OAuth (if applicable)

If your ToolMesh instance uses OAuth, ChatGPT redirects to the login page. Authorize access, and you are returned to ChatGPT with the connector authenticated.

ChatGPT supports **OAuth 2.1 with PKCE** and dynamic client registration. It queries `/.well-known/oauth-protected-resource` on the ToolMesh server to discover the authorization server.

### 4. Enable ToolMesh in a conversation

Open a **new chat**, click the **+ button** near the message composer, select **More > Developer Mode**, then **Add sources** and enable ToolMesh.

The connector must be **enabled in each new conversation** — it does not carry over.

### 5. Use your tools

Prompt naturally (e.g. "List my open GitHub issues", "Show server status"). ChatGPT shows expandable JSON payloads for each tool call. Write operations require **manual confirmation** before execution.

## Transport and authentication details

**Supported transports:** ChatGPT supports **Streamable HTTP** (recommended) and **SSE**. The runtime auto-detects the protocol. **stdio is not supported** — ChatGPT cannot launch local servers.

**Authentication:** The ChatGPT UI offers OAuth 2.1 or no authentication. Bearer token / API key authentication is not natively supported in the UI. If your ToolMesh instance uses API keys, you need to either:
- Configure OAuth authentication on ToolMesh instead (recommended for ChatGPT)
- Proxy through `mcp-remote` with a `--header` flag as a workaround

## Plan availability

| Plan | Developer Mode (full MCP) |
|------|:---:|
| **Free** | No |
| **Plus** | Yes (beta) |
| **Pro** | Yes (beta) |
| **Team** | Limited |
| **Business** | Yes (beta) |
| **Enterprise** | Yes (beta) |
| **Education** | Yes (beta) |

For Business, Enterprise, and Education plans, **workspace admins must enable Developer Mode** from Workspace Settings > Permissions & Roles before individual users can access it.

## Known limitations

- **Per-chat activation** — every new conversation requires manually enabling Developer Mode and selecting ToolMesh through the + > More > Developer Mode > Add sources flow. There is no "always on" setting.
- **Memory disabled** — ChatGPT cannot learn preferences or recall past interactions when using MCP tools.
- **Tool count** — servers exposing more than 30-40 tools can degrade model performance. ToolMesh lets you control which backends and tools are exposed per user via [authorization policies](/en/authorization/).
- **HTTPS only** — ChatGPT cannot connect to plain HTTP endpoints. For local development, use a tunneling service.

## Next steps

- [Getting Started](/en/getting-started/) — install ToolMesh and configure authentication
- [Authentication](/en/authentication/) — OAuth 2.1, API keys, and multi-user setup
- [Configuration](/en/configuration/) — all environment variables and config file reference