Grok Bot skill and MCP setup
Give Grok Bot a US number when a sign-up of yours needs a code, and eSIM data for your next trip. Point it at the VoidMob skill with your key stored as a Bot secret, and approve each purchase in chat.
- US numbersNumbers
- $0.15/code
- Dedicated numbersDedicated
- $16.99/mo
- eSIM planseSIM
- $3.49from
Read https://voidmob.com/skill.md and follow it. My VoidMob API key is in the VOIDMOB_API_KEY secret.Then ask Grok Bot
What's my VoidMob balance?A number back means the key and the install both work.
The Bot reads the skill from its computer and calls the VoidMob API with curl, using the secret by name and keeping its value out of the chat. Ask the Bot to save the process as a skill so later chats start from there.
What VoidMob adds to Grok Bot
Grok Bot is xAI's agent that works on a persistent cloud computer, shared by all your Bots, with a browser, a filesystem and a terminal. It can read a skill from a link and run its curl calls there, and it takes custom MCP servers, either a remote HTTPS server or a Command server that runs on that computer.
A US number when your sign-up asks for one
Ask for a number for the service you are signing up to. Grok Bot quotes the price from your balance, rents a US non-VoIP number once you agree and reads the code back to you, while you stay the one completing the sign-up.
SMS verificationA number for an account you keep
A dedicated monthly number stays yours and receives login and recovery codes from any service, so the Bot can fetch the latest code for one of your accounts when you ask.
Dedicated numbersTrip data, bought from chat
Tell it where and when you travel. It compares eSIM plans by data and validity, buys the one you pick and shows the QR code in the chat for you to scan on your phone.
eSIM data plansSet up VoidMob in Grok Bot
One step is yours whichever path you take: create an API key in the dashboard and top up the balance with crypto.
Create a key and fund the balance
Create a key under Developers, API Keys (it is shown once) and top up with crypto. The Bot can spend what is there and nothing more.
Add the key as a Bot secret
In the Bot's Secrets section, add
VOIDMOB_API_KEYwith the key as its value. The Bot sees the name, never the value, and redacts it from output.Point the Bot at the skill
Send the message in the console above. The Bot reads the skill, uses the secret by name in its curl calls, and can save it as a skill of its own.
Check the balance first
Ask the Bot for your VoidMob balance. A number back means the skill, the secret and the key all work, before anything is bought.
Set purchases to ask first
Add an Ask first rule for VoidMob's buying calls and answer each with Allow once, not Always allow. VoidMob's skill already tells the Bot to quote and wait for your yes.
A first task to try
Paste this to Grok Bot. The panel plays what the setup above makes happen.
I'm in Lisbon from Friday for a week. Find an eSIM with enough data for maps and messaging, show me two options with prices, and wait for my pick.Two fit seven days: 1 GB for 7 days at $2.99, or 2 GB for 15 days at $4.49. Both are 5G. Which one?
Europe · 1 GB · 7 days · 5G
Scan it in your phone's eSIM settings, or enter the LPA string by hand
Scan it before you fly. Most plans start counting days when the eSIM first connects.
Most plans start counting days when the eSIM first connects, so buying a few days early is fine. Ask the Bot later how much data is left and it reads the usage for you.
Checks before every charge
Two checks always run at VoidMob: the price you approved and your balance. Two more run inside your MCP server when you set them. A refusal at any of them charges nothing.
No SMS, no charge
A verification number stays open 15 minutes. If no SMS arrives, the price returns to the balance automatically, except on services marked non-refundable.
Keys you can pull
Give Grok Bot its own key and revoke it on the API Keys page whenever you like. It stops working at once.
Per-order limitIn your MCP server, when set
VOIDMOB_MAX_ORDER_CENTS=2500
$6.99 is under the $25.00 limit (passed)
Session budgetIn your MCP server, when set
VOIDMOB_BUDGET_CENTS=5000
$6.99 of $50.00 left (passed)
Price you approvedAt VoidMob, always
max_price_cents
Live $6.99, approved $6.99 (passed)
Your balanceAt VoidMob, always
prepaid, topped up by you
$42.10 covers it (passed)
When Grok Bot and VoidMob disagree
API calls come back unauthorized
The secret is missing or named differently, so the curl calls go out without the key.
Fix
Name the secret exactly
VOIDMOB_API_KEY, then ask the Bot to check your balance again.The Command MCP server starts but cannot reach the account
The secret did not reach the Command server's environment; xAI's docs describe secrets for the Bot's own commands and point servers that need secrets to Remote HTTPS.
Fix
Switch to the skill route, which reads the secret in the Bot's terminal. Never move the key into the command to make it work.
A routine never completes its purchase
Approvals requested by scheduled routines expire after about ten minutes.
Fix
Keep purchases in a chat you are watching, and leave routines the reading: balance, order status and eSIM usage.
Give Grok Bot a balance to draw on
Create an API key, top it up with crypto, and paste it where the setup above says. Prefer to look first? The MCP server runs on play money with no key.
Frequently Asked Questions
Common questions about VoidMob in Grok Bot.
VOIDMOB_API_KEY, then tell the Bot to read https://voidmob.com/skill.md and follow it. The skill runs the VoidMob API with curl on the Bot's computer, using the secret by name, and the Bot can save it as a skill for later chats.npx -y @voidmob/mcp, with the key in the VOIDMOB_API_KEY secret. xAI's docs recommend a remote HTTPS server for anything that needs secrets, and VoidMob's server runs locally, so the skill is the simpler route: it reads the same secret in the Bot's terminal.Based on Grok Bot's own docs: Grok Bot overview · Team bots · Security · Secrets · How-to · Approvals, security and privacy. Last checked .