Claude Code is Anthropic's AI coding agent that runs directly in your terminal and VS Code. With MCP (Model Context Protocol) support built in, you can give Claude access to external tools like AgentCall, letting it provision phone numbers, send SMS, extract OTP codes, configure inbound AI receptionists, and place outbound voice calls, all from your editor.

This guide walks you through connecting AgentCall's 23 MCP tools to Claude Code in under 2 minutes.

What You Need

Claude Code. Install via CLI (npm install -g @anthropic-ai/claude-code) or search "Claude Code" in the VS Code Extensions Marketplace and install the official Anthropic extension directly.
An AgentCall API key (free at agentcall.co/sign-up).

Step 1: Get Your AgentCall API Key

Sign up at agentcall.co/sign-up and navigate to the API Keys page in your dashboard. Copy your API key (it starts with ac_live_).

The Free plan gives you 1 US or Canada local number with no card on file (subsequent numbers and non-US/CA countries require a card), 10 SMS/month, 5 call minutes, 5 OTP extractions, and a 5-minute monthly trial of inbound AI voice. Plenty to build and test an integration.

Step 2: Add AgentCall MCP Server to Claude Code

The recommended path is the hosted endpoint. Open your terminal in VS Code and run:

claude mcp add agentcall \
  --transport http https://api.agentcall.co/mcp \
  --header "Authorization: Bearer ac_live_your_key_here"

Replace ac_live_your_key_here with your actual key. Same URL works for every MCP client; auth is handled by the Bearer header.

Prefer to run the server locally (air-gapped or air-gap-curious)? Use the npm package:

claude mcp add agentcall \
  --env AGENTCALL_API_KEY=ac_live_your_key_here \
  -- npx -y @agentcall/mcp-server

Step 3: Verify the Connection

Start Claude Code and ask it to list the available tools. You should see 23 AgentCall tools registered:

You: What MCP tools do you have for phone numbers?

Claude: I have access to AgentCall's MCP tools:
- provision_number. Get a new phone number.
- send_sms. Send a text message.
- wait_for_otp. Long-poll for an OTP verification code.
- initiate_ai_call. Make an AI-powered phone call.
- configure_inbound_ai. Set up incoming calls to be answered by an AI receptionist.
... and 16 more tools

Step 4: Start Using Phone Tools

Now you can ask Claude to perform phone operations directly. Here are some examples:

Provision a Phone Number

You: Provision a local US phone number for me

Claude: I'll provision a local US number for you.
[Calls provision_number with country: "US", type: "local"]

Done! Your new number is +1 (314) 555-0123
Number ID: num_abc123

Send an SMS

You: Send an SMS from my new number to +12125559876 saying "Hello from my AI agent"

Claude: [Calls send_sms]
SMS sent successfully.

Test OTP Verification

You: I entered my number in a signup form. Wait for the OTP code.

Claude: [Calls wait_for_otp with long-polling]
Got it! The verification code is: 847291

Make an AI Voice Call

You: Call +12125559876 and ask them about their business hours

Claude: [Calls initiate_ai_call with system prompt]
Call completed. Here's the transcript:
...

Set Up an Inbound AI Receptionist

You: Configure my number to act as a receptionist for "Acme Plumbing"
     that books appointments and answers FAQ.

Claude: [Calls configure_inbound_ai with a system prompt and voice]
Inbound AI is live on +1 (314) 555-0123.

Using via Smithery

AgentCall is also listed on Smithery, the largest MCP server registry. Install via the Smithery CLI:

npm install -g smithery
smithery mcp add agentcall/agentcall \
  --headers '{"agentcallApiKey":"ac_live_your_key_here"}'

Smithery also exposes its own hosted URL for the server at https://agentcall--agentcall1.run.tools, useful when you want Smithery's OAuth and token refresh instead of managing the Bearer header yourself.

All 23 Tools at a Glance

Once connected, Claude Code has access to these tools, plus four built-in MCP prompts (setup-agent-phone, send-and-track-sms, ai-outbound-call, setup-inbound-ai-receptionist):

Phone Numbers: provision_number, list_numbers, get_number, release_number, configure_inbound_ai, disable_inbound_ai
SMS: send_sms, get_inbox, get_message, wait_for_otp
Voice: initiate_call, initiate_ai_call, get_call, hangup_call, get_call_transcript, list_calls
Webhooks: create_webhook, list_webhooks, rotate_webhook_secret, delete_webhook
Usage: get_usage

Next Steps

Questions? Email support@agentcall.co.

How to Use AgentCall MCP Server with Claude Code in VS Code