Use asms with OpenAI API
Give your own OpenAI-powered agent asms as a remote MCP tool in the Responses API: verification codes and rented numbers in a few lines.
> Get me a US number for Telegram and give me the code when it arrives.
● asms.get_pricing({ "country": "us", "service": "telegram" }) → in stock
US Telegram numbers are in stock at the listed price, and you're only charged if a code arrives. Order one?
> Yes, go ahead.
● asms.create_otp_order({ "country": "us", "service": "telegram" }) → +1 347 •••-••18
● asms.poll_sms({ "orderId": "…" }) → code received
Your number is +1 347 •••-••18 and the Telegram code is 504913.
What you can ask OpenAI API
Once asms is connected, OpenAI API can order numbers, read the SMS they receive and check your account, all paid from your asms wallet.
Get a verification code
“Order a UK number for WhatsApp and wait for the code.”
Rent a number you keep
“Rent a US number for a month for our app's SMS login tests, and show me any texts it gets.”
Check the account
“What's my asms balance, and which orders are still waiting for a code?”
Setup
You need an asms API key: create one in your dashboard and keep it in the ASMS_API_KEY environment variable.
The quick way: paste a prompt
Paste this into OpenAI API. It reads this page and follows the steps for agents below.
Connect the asms MCP server to OpenAI API by following the steps for AI agents at https://asms.ai/agents/openai-api. My asms API key is in the ASMS_API_KEY environment variable; don't print it.Or step by step
- 1
Add asms as a tool
OpenAI doesn't store the key, so send it with every request. "always" makes the API return an approval request before each call; you approve it in your code.
pythonimport os from openai import OpenAI client = OpenAI() resp = client.responses.create( model="gpt-5", tools=[{ "type": "mcp", "server_label": "asms", "server_url": "https://asms.ai/mcp", "authorization": os.environ["ASMS_API_KEY"], "require_approval": "always", }], input="What's my asms balance, and what does a US Telegram code cost?", ) print(resp.output_text) - 2
Skip approvals for read-only tools
Let the model check prices and read codes freely, and approve only what spends.
require_approval"require_approval": {"never": {"tool_names": ["get_balance", "get_pricing", "get_inventory", "poll_sms", "list_active_orders", "get_rental_offers", "list_rentals", "read_rental_sms"]}}
For AI agents reading this page
If a user asked you to connect asms to OpenAI API, follow these steps in order.
- Check whether the ASMS_API_KEY environment variable is set, without printing its value. If it is not set, ask the user to create a key at https://asms.ai/dashboard#api-keys and set ASMS_API_KEY, then stop until they confirm.
- Register the server: add the tool { "type": "mcp", "server_label": "asms", "server_url": "https://asms.ai/mcp", "authorization": <ASMS_API_KEY>, "require_approval": "always" } to the Responses API request.
- Check it worked: send a request asking for the asms balance and check the response calls get_balance.
- Start read-only: call
get_balance, thenget_pricingorget_rental_offers, and report what you found. - Before any tool that spends from the wallet (
create_otp_order,rent_number), tell the user the price and wait for their OK. - Never create an asms account or API key, top up the wallet, or approve a sign-in on the user's behalf, and never print the key.
Reference
| MCP endpoint | https://asms.ai/mcp |
| Transport | Streamable HTTP (stateless) |
| Auth | OAuth sign-in with asms, or the header Authorization: Bearer <ASMS_API_KEY> |
| REST API | https://asms.ai/api-docs |
| For LLMs | https://asms.ai/llms.txt |
Tools
| Tool | What it does | Needs your OK? |
|---|---|---|
get_balance | Wallet balance | No |
get_pricing | Verification code prices | No |
get_inventory | Verification number stock | No |
create_otp_order | Order a verification number | Yes |
poll_sms | Check for the verification code | No |
list_active_orders | List verification orders | No |
cancel_order | Cancel a verification order | Yes |
get_rental_offers | Number rental prices | No |
rent_number | Rent a phone number | Yes |
list_rentals | List rented numbers | No |
read_rental_sms | Read a rented number's SMS | No |
cancel_rental | Cancel a rental for a refund | Yes |
Other agents and tools
Questions
What does it cost?+
Connecting is free. You pay from your asms wallet: verification codes from $0.50, charged only when a code arrives and refunded automatically when none does, and rented numbers priced by country and period. Top up by card, PayPal or crypto.
Will OpenAI API spend money without asking?+
Ordering a code and renting a number are marked as spending tools, so clients that support it ask for your approval first, and asms tells the agent to confirm the price with you before buying. Reading prices, balances and messages never spends anything.
What's the difference between a code and a rented number?+
A verification code order gives you a number for one code, for one service, and refunds itself if nothing arrives. A rented number is yours for a set period, from a day to a year, and receives every SMS sent to it: useful for testing your own app's SMS login or for an account you'll need to verify again later.
How do I disconnect it?+
Delete the API key in your asms dashboard, or remove asms under Connected apps if you signed in. Either one cuts off access straight away.
Give OpenAI API a phone number
Create an account, top up from a few dollars, and connect. Codes from $0.50, refunded automatically when none arrives.