Build an AI voice agent with Claude Code and ElevenLabs in just a few hours. Learn how to create an intelligent phone assistant with knowledge bases, workflows, tools, guardrails, testing, and Twilio integration.
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Why Claude Code + ElevenLabs Is Changing Voice AI
Creating an AI voice agent used to require multiple vendors, complex infrastructure, speech recognition APIs, text-to-speech services, telephony providers, and weeks of engineering effort.
That’s no longer the case.
With Claude Code and ElevenLabs ElevenAgents, you can build an intelligent, production-ready voice assistant in just a few hours using natural language prompts.
Whether you’re building:
- Customer support
- AI receptionist
- Portfolio assistant
- Internal operations assistant
- Appointment scheduler
- Sales qualification bot
the entire workflow can now be built without writing hundreds of lines of backend code.
In this guide, you’ll learn exactly how.
What Is ElevenAgents?
ElevenAgents is ElevenLabs’ platform for creating conversational voice agents that combine:
- Ultra-realistic AI voices
- Large Language Models
- Knowledge retrieval (RAG)
- Multi-step workflows
- Tool calling
- Guardrails
- Testing
- Native phone integrations
Instead of wiring multiple AI services together, everything lives inside one platform.
Why Use Claude Code?
Claude Code lets developers create and configure AI systems using natural language prompts.
Instead of manually editing configuration files, you simply tell Claude what you want.
Example:
Create a knowledgeable product expert using ElevenLabs v3 voice and GLM 4.5.
Claude generates the configuration automatically.
This dramatically reduces development time.
What You Can Build
In one afternoon, you can create:
AI Customer Support
Answer product questions 24/7 using your documentation.
AI Receptionist
Handle inbound calls, qualify leads, and transfer to human agents.
Portfolio Assistant
Turn your personal website into an interactive voice experience.
Overnight DevOps Assistant
Receive voice briefings about:
- CI failures
- Deployments
- GitHub issues
- Monitoring alerts
Multilingual Help Desk
Support customers in multiple languages using automatic language detection.
Why Voice AI Feels More Human Today
Recent advances have dramatically improved conversational AI.
Modern voice agents now offer:
- Low latency (~75 ms)
- Natural interruptions
- Turn-taking
- Emotional speech
- Dynamic pacing
- Laughter
- Hesitation
- Expressive prosody
These improvements make conversations feel significantly more natural than earlier voice bots.
Step 1: Install the ElevenLabs Skill
Install the ElevenLabs Claude Code skill globally.
npx skills add elevenlabs/skills
Next, configure your API key.
Prompt Claude:
Set up the elevenlabs key using the setup-api-key skill.
Security Tip
Limit the API key to:
- agents-write permissions
- daily spending limits
This protects against accidental credit usage.
Step 2: Create Your First Voice Agent
The quickest way to get started is by creating a basic conversational agent.
Prompt:
Create an ElevenAgent: a warm, knowledgeable product expert. Use a v3 conversational voice and GLM 4.5 as the LLM. Return the dashboard URL.
Claude creates:
- Voice
- Persona
- Language model
- Dashboard configuration
No manual setup required.
Step 3: Add a Knowledge Base
Voice agents become much more useful when they can answer questions using your own documentation.
ElevenAgents supports Retrieval-Augmented Generation (RAG).
Instead of relying solely on the LLM’s training data, it searches indexed documentation before generating a response.
Example prompt:
Add a knowledge base to my agent.
Index:
https://elevenlabs.io/docs/eleven-agents/overview
./README.md
Enable auto reindex.
Benefits include:
- always up-to-date documentation
- fewer hallucinations
- accurate technical answers
- automatic content refresh
Step 4: Build Multi-Step Workflows
Real conversations involve different intents.
Instead of one giant system prompt, ElevenAgents lets you create workflow nodes.
Example:
Greeting
โ
Intent Classification
โ
Answer from Knowledge Base
OR
Transfer to Human
โ
Conversation Wrap-up
Prompt:
Add a workflow to my agent: greeting, classify intent, then branch to either answer from KB or escalate to human, then wrap up.
Benefits include:
- easier maintenance
- reusable conversation logic
- higher response quality
- scalable architecture
Step 5: Add Powerful Tools
Voice agents become truly useful when they can interact with applications.
ElevenAgents supports three tool types.
Client Tools
Interact with your frontend.
Example:
show_help_article(article_id)
The agent can display documentation while talking.
Webhook Tools
Connect your backend APIs.
Example:
https://wttr.in/{location}?format=j1
The agent can answer:
What’s the weather in New York?
using live data.
Built-In Tools
Ready-to-use capabilities include:
- end call
- language detection
- call transfer
- telephony actions
Prompt:
Add three tools:
Client tool:
show_help_article
Webhook:
get_weather
Enable:
end_call
language_detection
Step 6: Add Guardrails
LLMs occasionally drift from intended behavior.
Guardrails provide an independent safety layer.
Recommended protections:
- Prompt injection defense
- Topic focus enforcement
- Pricing restrictions
- Billing protection
- Sensitive operation blocking
Example prompt:
Enable:
Focus
Prompt Injection Protection
Custom rules:
No pricing guarantees
No speculation
No billing modifications
This helps prevent incorrect or risky responses before users hear them.
Step 7: Test Everything
Before deploying, verify that your agent behaves correctly.
ElevenAgents supports three testing categories.
Response Tests
Check:
- greeting
- tone
- professionalism
Tool Tests
Verify correct tool usage.
Example:
When users ask about password resets,
the agent should invoke:
show_help_article
Simulation Tests
Run full conversations to validate workflows.
Example:
If users ask about pricing,
the agent should transfer them to sales.
Prompt:
Create:
Greeting test
Password reset tool test
Pricing simulation
Testing early helps catch issues before customers encounter them.
Step 8: Put Your Agent on a Phone Number
Your agent can run inside the ElevenLabs dashboard, but production deployments often require phone support.
ElevenAgents integrates directly with:
- Twilio
- SIP
- Vonage
- Telnyx
- Plivo
- Genesys
The easiest option is Twilio.
Prompt:
Connect my Twilio account.
Reserve a +1 number.
Assign it to my ElevenAgent.
Return the phone number.
The platform automatically configures:
- voice webhooks
- audio routing
- inbound calls
- outbound calls
No manual TwiML configuration is needed.
Best Practices for Production Voice Agents
To deliver the best experience:
- Use a clear, consistent persona.
- Keep knowledge sources updated with auto-reindexing.
- Enable prompt injection protection and custom guardrails.
- Test greeting tone, tool calls, and conversation flows before launch.
- Restrict API permissions and set spending limits.
- Transfer sensitive requests such as billing or legal issues to human agents.
- Monitor conversations regularly and refine workflows based on real user interactions.
Why This Workflow Is Different
Traditional voice AI required stitching together:
- Speech recognition
- Text-to-speech
- LLM APIs
- RAG systems
- Telephony providers
- Backend orchestration
Claude Code and ElevenAgents simplify this into a single, prompt-driven workflow. Developers can configure sophisticated voice agents using natural language, while the platform manages retrieval, tool execution, workflows, and telephony behind the scenes.
Frequently Asked Questions
Can I build a voice agent without coding?
Yes. Claude Code allows you to configure most of the agent using natural-language prompts. Some integrations or custom APIs may still require development work.
Do I need Twilio?
No. You can test your agent directly in the ElevenLabs dashboard. Twilio (or another supported provider) is only needed when you want a production phone number.
Can the agent use my documentation?
Yes. ElevenAgents supports Retrieval-Augmented Generation (RAG), allowing it to search indexed documentation, FAQs, and local files before responding.
Can the agent call external APIs?
Yes. Webhook tools let the agent retrieve or update data in external systems, while client tools can interact with your application’s user interface.
Is ElevenAgents suitable for production?
Yes. Features such as workflows, testing, guardrails, and native telephony integrations are designed to support production deployments.
Final Thoughts
Voice AI has matured rapidly. What once required multiple vendors, custom infrastructure, and weeks of engineering can now be assembled in hours with Claude Code and ElevenLabs.
By combining expressive AI voices, Retrieval-Augmented Generation, workflow automation, tool integrations, guardrails, and native telephony support, you can create voice experiences that feel more natural, respond more accurately, and scale with your business.
Whether you’re building a customer support assistant, an AI receptionist, or an interactive portfolio guide, this workflow provides a practical path from idea to deployment.
Ready to build your own AI voice agent?
