What is a ChatGPT MCP connector?

In ChatGPT, a custom MCP connector (also called a developer-mode app) is a remote MCP server ChatGPT reaches over HTTPS. You add the server URL, complete auth if required, and ChatGPT can call that server's tools from a conversation. OpenAI also uses the words app and plugin for related surfaces. DialMCP is the phone-call server, not a ChatGPT Apps SDK widget.

How do I add DialMCP to ChatGPT?

On ChatGPT web, turn on Developer mode under Settings, Security and login. Open ChatGPT Plugins, click plus, and paste https://mcp.dialmcp.com/mcp. Choose OAuth, finish DialMCP sign-in and SMS verification, then confirm Scan Tools shows place_call, get_call, end_call, and list_calls. In a new chat, enable Developer mode from the tools menu and select DialMCP before asking it to place a call.

Can ChatGPT Plus or Pro place a DialMCP call?

place_call is a write tool: it starts a real phone call. OpenAI's developer-mode guide (checked 2026-09-18) lists Plus and Pro as eligible for full read and write MCP tools on the web. The Help Center article on developer mode still says full MCP write is rolling out to Business, Enterprise, and Edu, with Pro limited to read/fetch. If Scan Tools hides write tools or ChatGPT refuses place_call, use Claude, Cursor, or Codex instead.

Can ChatGPT use a local stdio MCP server?

Not directly. ChatGPT only reaches remote MCP servers over the network. npx dialmcp-connector is for local clients. DialMCP is already hosted, so paste https://mcp.dialmcp.com/mcp. For a private server you are building yourself, OpenAI documents Secure MCP Tunnel; that is not how you connect DialMCP.

Client recipe

Add DialMCP as a ChatGPT MCP connector.

Updated September 18, 2026

ChatGPT can call a remote MCP server from a conversation. That custom connection is what people search for as a ChatGPT MCP connector. OpenAI's own screens also say developer-mode app or plugin. Same object: a public HTTPS MCP endpoint ChatGPT reaches as a client.

DialMCP is that endpoint for phone calls, not a ChatGPT Apps SDK widget and not a listing in OpenAI's plugin directory. Paste the hosted URL, finish OAuth and SMS verification, then ask ChatGPT to place a specific call. Snippets for other hosts live on client setup.

Remote only. ChatGPT does not launch local stdio servers. Do not add npx dialmcp-connector here. The URL is https://mcp.dialmcp.com/mcp. Why remote MCP exists: remote MCP servers explained.

What you need

ChatGPT on the web. Custom MCP apps are not on mobile (OpenAI Help Center, checked September 18, 2026).
A plan that can turn on Developer mode. OpenAI's developer-mode guide lists Plus, Pro, Business, Enterprise, and Education.
A US or Canadian mobile number. DialMCP verifies it by SMS and uses it as caller ID.
Write-capable tools if you want an actual call. See the plan caveat below.

1. Turn on Developer mode

In ChatGPT: Settings → Security and login → Developer mode. That is the path in OpenAI's current connect docs. Workspace menus also show Settings → Apps → Advanced Settings, or an admin toggle under Workspace Settings → Permissions & Roles → Connected Data. Labels move. If you cannot create a custom MCP app, Developer mode is off or your workspace admin has not granted it.

2. Add the DialMCP URL

Open ChatGPT Plugins (or Settings → Apps → Create on a workspace).
Click the plus button. Developer mode must already be on or this plus button will not create a custom MCP app.
Name: DialMCP. One-line description: phone calls from your verified number.
Connection: public endpoint. URL: https://mcp.dialmcp.com/mcp (include /mcp).
Authentication: OAuth. Do not pick "no auth".
Create / Scan Tools. Complete the DialMCP browser sign-in and SMS code when prompted.

Scan Tools should list four tools: place_call, get_call, end_call, and list_calls. Names and schemas: tool reference. The JSON-RPC methods ChatGPT sends for you are tools/list and tools/call.

URL:        https://mcp.dialmcp.com/mcp
Transport:  Streamable HTTP (OpenAI also lists SSE)
Auth:       OAuth 2.1

There is no API key to paste. The first connection is the OAuth sign-in. If the scan fails, confirm the URL is exact and that you finished SMS verification. General remote vs stdio notes are on install.

3. Use it in a chat

Start a new conversation on the web.
Open the tools / plus menu, choose Developer mode, and select DialMCP. Selection applies to that message.
Ask for one concrete call: destination, who it is for, and the objective. Example: "Use DialMCP place_call to phone the clinic at +1… and confirm Tuesday 3pm under my name."
Approve the write. ChatGPT treats tools without readOnlyHint as writes and asks before sending. place_call starts a real PSTN call. Review the destination and objective.
The first result is a call ID, not a transcript. Ask ChatGPT to poll get_call until the call is done, then read the structured outcome, transcript, and recording link.

Be explicit about the app and tool name if ChatGPT tries to browse or invent a phone API instead. OpenAI's own prompting notes say to name the server and tool and to disallow alternatives.

Plan caveat: write tools

A useful DialMCP session needs write tools. place_call and end_call change the world (a phone rings). get_call and list_calls only read.

Two official OpenAI pages disagreed on who gets writes when this page was checked on September 18, 2026:

The developer-mode guide says Developer mode is full MCP, read and write, for Plus, Pro, Business, Enterprise, and Education on the web.
The Help Center article says full MCP write is rolling out to Business, Enterprise, and Edu, and that Pro users can connect MCPs with read/fetch permissions only.

Trust Scan Tools on your account, not a blog post. If place_call is missing, greyed out, or ChatGPT will only fetch, DialMCP cannot place the call in that ChatGPT session. Use Claude, Cursor, Codex, or another remote MCP client instead. Do not try to smuggle a call through deep research: OpenAI says deep research may use custom apps for read/fetch only, and agent mode will not use custom apps.

What this is not

Not a local config file. There is no mcp.json for ChatGPT. File-path snippets are configuration examples.
Not the stdio bridge. npx dialmcp-connector is for hosts that only speak local MCP. ChatGPT is a remote client.
Not an Apps SDK plugin. DialMCP has no ChatGPT UI component. You are connecting a tools-only remote server.
Not a bypass of safety rules. Disclosure, caller ID, hours, rate limits, and opt-outs stay on the hosted server. Read Safety before the first call.

After it connects, the call lifecycle is the same as every other client: tools. Back to the docs hub.