Why do I need the API at all?

Vapi's dashboard steps for an MCP tool take only a server URL. The key has to go in a header, and the API is where Vapi takes headers.

Can each caller have their own alarms?

Not on Vapi with one tool: the header is fixed, so every caller acts as the key's owner. If you need a key per caller, Retell can pass one with each call; see [Connect LFG Alarm to Retell](/agents/retell).

Does the alarm ring during the call?

No. It rings on the phone with the LFG Alarm app, at the time set. Time alarms are real alarms on both iPhone and Android and ring through silent mode.

Does LFG Alarm hear the call?

No. LFG Alarm only receives what the assistant sends when it uses LFG Alarm's tools, never the audio.

Connect LFG Alarm to Vapi

Before you start

Get the LFG Alarm app on your phone from Google Play or the App Store, and sign in. The assistant makes the alarms; the app is what rings them.
A personal key, since a phone assistant cannot do a sign-in. Make one below.
Your Vapi private API key, to create the tool with one request.

A key acts as you. Your Vapi assistant sets alarms on the key owner's phone, whoever is calling it. That is right for your own assistant or a small team where you are the one to wake. Keep LFG Alarm off assistants that the public can call, because every caller would be setting alarms on your phone. Vapi headers are fixed per tool, so there is no way to give each caller their own key.

Make a key

In LFG Alarm, open Settings > Connected AI apps, on lfg.gm or in the app.
Tap Make a key, name it after the assistant (for example "Vapi"), and tap Make the key.
The key is shown once, with Copy and Done: "Copy it now. It won't be shown again." Copy it, keep it ready for the next step, then tap Done.
It now shows in the list as Personal key, with when it was last used.

The screen says it plainly: "For an AI app that asks for a key instead of a sign-in, like Manus, a coding agent or your own script. A key acts as you, so keep it out of any agent other people use."

Keys start with lfg_pat_, work only at the LFG Alarm MCP server, and you can have up to 20. A key has the same plan limits as signing in.

Connect it

1. Create the tool through the API. In a terminal, with your Vapi private key in VAPI_API_KEY and your LFG Alarm key in LFG_KEY:

curl -X POST https://api.vapi.ai/tool \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "type": "mcp",
    "function": { "name": "mcpTools" },
    "server": {
      "url": "https://mcp.lfg.gm",
      "headers": { "Authorization": "Bearer '"$LFG_KEY"'" }
    },
    "metadata": { "protocol": "shttp" }
  }'

The address is https://mcp.lfg.gm, with no /mcp on the end. shttp is Streamable HTTP, Vapi's default; its older SSE option is on the way out. The reply includes the new tool's id.

2. Add it to your assistant. In the Vapi dashboard, open Assistants, pick your assistant, open its Tools tab, choose the tool you just made, and click Publish.

3. Tell the assistant when to use it. In the system prompt: "When the caller asks to be woken or reminded at a time, set an LFG Alarm, then say the time it rings. Do not read out links."

We could not confirm whether Vapi's dashboard has since gained a headers field for MCP tools. If yours shows one, you can put the same header there instead of using the API.

Keep calls quick

Vapi brings in every tool the server offers, and fetches the list when each call starts. LFG Alarm has more than a dozen tools, so the model has a fair bit to read before it speaks. Two things help:

Keep the prompt narrow: name the one or two things the assistant does with LFG Alarm, such as set a time alarm and list alarms.
Keep answers short. Each alarm comes back with a link, a share picture and a message; on a call, the assistant only needs to say the time and the name.

What fits

Your own phone assistant. Call it on the drive home: "alarm at 6:10 tomorrow, and tell Alex too." It sets a friends alarm and, once you confirm, adds your friend by username, so both phones ring.
An after-hours line for one owner. A small business assistant takes a late call and sets "Call back the plumber" for 8:00 on the owner's phone.
A heads-up for something online. "Ring me when [channel] goes live", spoken on a walk, becomes a post alarm.

Try it

Once the tool is published, call your assistant and say:

try this

Have your AI agent make it.

Paste this into ChatGPT, Claude, Grok or any AI agent that can add a connector, not into the LFG Alarm app. The setup steps come with it: get the LFG Alarm app, connect it to your agent once, and your agent makes the alarm in your account.

Set an LFG Alarm for 6:10 tomorrow morning called "Gym", and tell me when it goes off.

Already have the LFG Alarm app and connected it to your AI agent?

Why it works. One time alarm and the time spoken back, the quickest proof that the header, the tool and the assistant all work.

More ideas: "What alarms do I have tomorrow?", "Turn off my Gym alarm", or "Make a friends alarm for Saturday at 8 called Hike and add [username]". Through a key, LFG Alarm can set time, price, post, event and anything alarms, pick a sound or a look from the library, and add your friends or a whole group once you confirm. Each alarm comes back with its link, a share picture with a QR code and a message ready to send. Wallet and trader alarms are made in the app. See Using LFG Alarm from your AI agent.

If it does not work

The curl request fails. A 401 means the Vapi key is wrong; that is the first Authorization header. Check the quotes around $LFG_KEY came through, and the JSON is valid.
The assistant has no LFG Alarm tools. Check the tool is on the assistant's Tools tab and that you clicked Publish.
Tools load but every call fails. The LFG Alarm header is wrong. In LFG Alarm, the key's last used time stays empty. Make a new key and create the tool again.
Long silence at the start of calls. That is the tool list loading; see Keep calls quick above.
It refuses an alarm. A key has the same plan limits as signing in. For plans and pricing, go to lfg.gm.
Still stuck? Write to us from the support page.

Disconnect

In LFG Alarm, open Settings > Connected AI apps and tap Disconnect beside the key. It stops working at once. You can also remove the tool from the assistant in Vapi. Your alarms stay in your account and keep ringing.

Learn more

Sources and further reading

LFG Alarm is not affiliated with Vapi.