AgentLine MCP tool for ADK¶

Supported in ADKPythonTypeScript

The AgentLine MCP Server connects your ADK agent to AgentLine, an AI-native telephony platform. This integration gives your agent the ability to provision US phone numbers, make and receive voice calls, retrieve transcripts, read inbound SMS, and manage billing using natural language.

Use cases¶

Autonomous Phone Calls: Have your agent call a US number, hold an AI-powered conversation with a custom greeting and system prompt, then return the full transcript.
Inbound Voice Agents: Create a voice agent, attach a phone number, and let AgentLine answer inbound calls with the agent's prompt, greeting, and voice.
Phone Number Management: Provision a US local or toll-free number with a preferred area code and assign it to an agent.
Inbound SMS: Read SMS that callers send to the agent's number and poll for sms.received events.
Transcripts and Events: List calls, hang up an in-progress call, and poll or peek at the event mailbox for call.completed and call.owner_task results.
Voice and Billing: Choose a TTS voice preset and check account balance before placing calls or buying numbers.

Prerequisites¶

Create an AgentLine account
Generate an API key with the email one-time-code flow. See Authentication

Use with agent¶

PythonTypeScript

Remote MCP Server

from google.adk.agents import Agent
from google.adk.tools.mcp_tool import McpToolset
from google.adk.tools.mcp_tool.mcp_session_manager import StreamableHTTPConnectionParams

AGENTLINE_API_KEY = "YOUR_AGENTLINE_API_KEY"

root_agent = Agent(
    model="gemini-flash-latest",
    name="agentline_agent",
    instruction="Help users make phone calls, read inbound SMS, and manage phone numbers",
    tools=[
        McpToolset(
            connection_params=StreamableHTTPConnectionParams(
                url="https://api.agentline.cloud/mcp",
                headers={
                    "Authorization": f"Bearer {AGENTLINE_API_KEY}",
                },
            ),
        )
    ],
)

Remote MCP Server

import { LlmAgent, MCPToolset } from "@google/adk";

const AGENTLINE_API_KEY = "YOUR_AGENTLINE_API_KEY";

const rootAgent = new LlmAgent({
    model: "gemini-flash-latest",
    name: "agentline_agent",
    instruction: "Help users make phone calls, read inbound SMS, and manage phone numbers",
    tools: [
        new MCPToolset({
            type: "StreamableHTTPConnectionParams",
            url: "https://api.agentline.cloud/mcp",
            transportOptions: {
                requestInit: {
                    headers: {
                        Authorization: `Bearer ${AGENTLINE_API_KEY}`,
                    },
                },
            },
        }),
    ],
});

export { rootAgent };

Available tools¶

Agents¶

Tool	Description
`create_agent`	Create a voice agent with a name, system prompt, greeting, and voice
`list_agents`	List all agents
`get_agent`	Get details for a specific agent
`update_agent`	Update an agent's prompt, greeting, voice, or owner phone
`delete_agent`	Delete an agent

Phone numbers¶

Tool	Description
`buy_phone_number`	Provision a US local or toll-free number and attach it to an agent
`list_phone_numbers`	List phone numbers on the account

Voice calls¶

Tool	Description
`make_outbound_call`	Place an outbound call from an agent's number
`list_calls`	List recent calls
`get_call_details`	Get status and metadata for a call
`get_call_transcript`	Get the full `{role, text, timestamp}` transcript
`hangup_call`	End an active call

SMS¶

Outbound SMS is not available. Inbound messages arrive as sms.received events.

Tool	Description
`list_messages`	List inbound SMS for an agent

Events¶

The poll_events tool consumes pending events. Use peek_events to inspect the queue without deleting it. Common event_type values include call.received, call.completed, call.owner_task, and sms.received.

Tool	Description
`poll_events`	Consume pending call and SMS events from the mailbox
`peek_events`	Preview pending events without consuming them

Billing¶

Tool	Description
`get_account_balance`	Get the current account balance
`get_expenditure_breakdown`	Get spending for the current period

Voice¶

Voice presets include female-1, female-2, female-3, male-1, male-2, and male-3. Per-call and per-agent settings override the account default.

Tool	Description
`list_available_voices`	List TTS voice presets
`get_account_voice`	Get the account-level default voice
`set_account_voice`	Set the account-level default voice
`reset_account_voice`	Reset the account voice to the platform default

Configuration¶

The remote AgentLine MCP server authenticates with a Bearer API key. Keys use the al_live_ prefix. Legacy sk_live_ keys are also accepted.

Setting	Description	Default
`Authorization` header	`Bearer al_live_...`	Required
MCP URL	Hosted Streamable HTTP endpoint	`https://api.agentline.cloud/mcp`

Phone numbers are E.164 (for example, +12125557890). Each agent can have one active number. Numbers are US-only.