ChatGPT can plan a phone call in seconds: who to ring, what to ask, what to say if they push back. What it cannot do on its own is pick up the phone. Assindo can. Assindo is an AI phone assistant: it calls businesses for you, works through phone menus, waits on hold, talks to whoever answers, and writes up what they said. Add Assindo to ChatGPT as a custom MCP server and ChatGPT can hand the call to Assindo, then read you the result.
One thing to know first: as of October 2026, this works fully only on ChatGPT Business, Enterprise and Edu workspaces. Personal plans are more limited; see the next section before you start.
Which ChatGPT Plans Can Use It
As of October 2026, here is what OpenAI documents. Assindo's create_task and send_chat_message tools create things, so ChatGPT treats them as write actions; that is what decides whether Assindo can actually place a call for you.
| ChatGPT plan | Add a custom MCP server | Write actions (have Assindo place a call) |
|---|---|---|
| Business | Yes, on the web, if your admin allows it | Yes (full MCP support, in beta) |
| Enterprise and Edu | Yes, on the web, if your admin allows it | Yes (full MCP support, in beta); admins can also limit actions per app |
| Pro | Yes, in developer mode on the web | No: read and fetch only, so ChatGPT cannot create an Assindo task |
| Plus | Not documented by OpenAI's help center; some Plus users report the option is still rolling out | Not documented; do not rely on it |
| Free and Go | No | No |
Where it works: you add custom MCP servers in ChatGPT on the web. OpenAI's help center says they cannot be added on mobile.
In a workspace: admins and owners control who can create custom apps and publish them to the workspace, and workspace security settings (including Lockdown) apply. If you are on Business, Enterprise or Edu and do not see the option, ask your admin.
On a personal plan: if you are on Plus or Pro, use Assindo directly in the Assindo app, or connect it to Claude, which allows custom connectors on every plan. OpenAI has changed these rules several times, so check its help center for your plan.
What You Need
- ChatGPT on the web, on a Business, Enterprise or Edu workspace where your admin lets you add custom MCP servers (see the plan table above).
- An Assindo account. Free to create in the Assindo app (iOS, Android, or web at web.assindo.com). Calls use your Assindo plan's minutes.
-
The Assindo MCP server:
https://mcp.assindo.com/mcp(Streamable HTTP, OAuth sign-in).
How to Connect It
- Open ChatGPT on the web, signed in to your Business, Enterprise or Edu workspace, and go to ChatGPT Plugins (chatgpt.com/plugins).
- Select the plus button, then Add custom MCP server.
- Enter a name, for example
Assindo, and optionally a description. - Under Connection, enter this Server URL:
https://mcp.assindo.com/mcp - For authentication, choose OAuth.
- Review the risk warning and select I understand and want to continue.
- Select Create as a plugin, then review the tools ChatGPT found on the server.
- Install the plugin and sign in with your Assindo account (Google, Apple or email, the same login as the app).
Assindo supports dynamic client registration, so there is no client ID or secret to paste: ChatGPT registers itself when you sign in. The Assindo sign-in page shows chatgpt.com with a Verified badge, so you know the request came from ChatGPT.
To use it, type @ in the prompt box and select the Assindo plugin, then ask for the call.
Try It
- "Call a bakery near me and ask if they can do a cake for 12 by Saturday."
- A few minutes later: "How did the bakery call go?"
- "Tomorrow at 9am, have Assindo call my internet provider and ask why my bill went up."
ChatGPT should ask the questions a good assistant would (which bakery, when is the party), then create the task. Assindo phones the bakery, asks about the cake, the price and how much notice they need, and the result shows up in the Assindo app and back in ChatGPT.
What ChatGPT Can Ask Assindo to Do
Assindo gives ChatGPT three tools, the same things you do in the Assindo app:
-
Create a task (
create_task). A phone call (book, ask, cancel, follow up), a post on X or LinkedIn, something at a set time, or research. The task description is all Assindo sees, so ChatGPT should include the business, its number if known, exactly what to ask, and anything to avoid ("info only, do not book"). -
Check a task's result (
get_task_result). The status, what Assindo found out, and the call summary. A call usually takes 2 to 5 minutes. -
Send Assindo a message (
send_chat_message). Ask what happened on a call, what is on your task list, or hand over a request in plain words.
Troubleshooting
I do not see "Add custom MCP server"
Custom MCP servers are a ChatGPT web feature, not available in the mobile app. On Free and Go the option does not exist; on Plus it is not documented and may not appear. In a Business, Enterprise or Edu workspace, your admin decides who can add them, and workspace security settings (including Lockdown) apply. If the option is missing, ask your workspace admin.
Assindo connects but never places the call
You are probably on a plan with read and fetch access only, such as Pro. ChatGPT can see Assindo's tools but cannot run create_task, which is a write action. Use a Business, Enterprise or Edu workspace, or make the request in the Assindo app.
The sign-in keeps coming back
- Create your Assindo account in the Assindo app first. The connector signs you in to an existing account; it does not create one, and a new login shows "no Assindo account for this sign-in".
- Use the same sign-in method as the app (Google, Apple or email). A different Google account is a different Assindo account.
- Finish the sign-in in the window ChatGPT opened, then return to ChatGPT. If it still loops, remove the plugin and add it again: a fresh sign-in replaces the old one.
A call did not happen
Calls follow the same rules as the app: business hours only, no redialing someone who just declined, and your Assindo plan's minutes. If your plan has run out of minutes, the task result says so; check your plan in the Assindo app.
FAQs
Does ChatGPT dial the number itself?
No. ChatGPT hands the job to Assindo as a task, and Assindo's own assistant places the call with the same rules as the app.
Can I use it with ChatGPT Plus or Pro?
Not fully, as of October 2026. OpenAI's help center limits Pro to read and fetch permissions for custom MCP servers and does not list Plus at all, so ChatGPT cannot ask Assindo to place a call on either. Full support, including write actions, is for Business, Enterprise and Edu workspaces.
Does it cost extra?
No. Calls and tasks count against your normal Assindo plan, exactly as if you made them in the app.
Does it work in the ChatGPT desktop app or Codex?
The ChatGPT desktop app, the Codex CLI and the Codex IDE extension share Codex's MCP settings instead: see Use Assindo in Codex.
Does Assindo work with other AI apps?
Yes. The same server works in Claude, Meta Muse, OpenClaw and several coding tools: see the list of AI apps that work with Assindo. Assindo is also listed in the official MCP Registry as com.assindo/assindo.
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Want ChatGPT to make your next phone call? Get Assindo and connect it.
Sources
- Connecting custom MCP servers in ChatGPT, OpenAI Help Center, accessed October 2026
- Add custom MCP server, OpenAI developer docs, accessed October 2026
- Connect from ChatGPT, OpenAI Apps SDK docs, accessed October 2026
- Missing "Add custom MCP" for users, OpenAI Developer Community, October 2026
Originally published at https://assindo.com/news/use-assindo-in-chatgpt
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