AI Phone Agent
Voice Agents With Tool Use
Deploy an AI phone agent that holds real conversations, calls tools mid-call (calendar, CRM, webhooks), and runs both inbound and outbound from a single profile. Sub-second latency, full REST API.
What is an AI phone agent?
An AI phone agent is a voice agent that holds real-time spoken phone conversations and takes structured actions during the call — booking a meeting, looking up a record, updating your CRM, firing a webhook. The “agent” framing matters: unlike a static voicebot, an AI phone agent reasons, plans, and uses tools.
Phone Stack AI phone agents run on Google Gemini Live for sub-second voice latency, Anthropic Claude for high-quality reasoning and tool use, and Twilio for the telephony layer. The result is a phone agent that sounds human and actually completes the work.
What an AI phone agent can do
Live availability check, slot booking, confirmation send
Create + update records in HubSpot, Salesforce, or any REST CRM
Cite docs and answer accurately mid-conversation
Send a Stripe link via SMS while on the call
Trigger personalized follow-up email from a template
Fire any HTTP request — your backend, your logic
How AI phone agents work
- 1.Voice in. Twilio routes the audio over a WebSocket to the agent runtime.
- 2.Reason. Gemini Live streams the conversation; Claude handles tool decisions.
- 3.Act. The agent calls tools (calendar, CRM, webhook) and incorporates results into the reply.
- 4.Voice out. Sub-second response with native barge-in support.
- 5.Wrap. Recording, transcript, summary, scoring, and CRM update — all automatic.
Part of the Phone Stack AI call center
AI Phone Agent FAQs
Build your first AI phone agent today
15-minute setup. 30 free minutes. Full API.