Agent skill
elevenlabs-agents
Build conversational AI voice agents with ElevenLabs Platform. Workflow: configure agent, add tools and knowledge base, integrate SDK, test, deploy. Supports React, React Native, and Swift SDKs. Use when building voice agents, AI phone systems, or troubleshooting @11labs deprecated packages, webhook errors, CSP violations, localhost allowlist, or tool parsing errors.
Install this agent skill to your Project
npx add-skill https://github.com/jezweb/claude-skills/tree/main/plugins/integrations/skills/elevenlabs-agents
SKILL.md
ElevenLabs Agent Builder
Build a production-ready conversational AI voice agent. Produces a configured agent with tools, knowledge base, and SDK integration.
Packages
npm install @elevenlabs/react # React SDK
npm install @elevenlabs/client # JavaScript SDK (browser + server)
npm install @elevenlabs/react-native # React Native SDK
npm install @elevenlabs/elevenlabs-js # Full API (server only)
npm install -g @elevenlabs/agents-cli # CLI ("Agents as Code")
DEPRECATED: @11labs/react, @11labs/client -- uninstall if present.
Server-only warning: @elevenlabs/elevenlabs-js uses Node.js child_process and won't work in browsers. Use @elevenlabs/client for browser environments, or create a proxy server.
Workflow
Step 1: Create Agent via Dashboard or CLI
Dashboard: https://elevenlabs.io/app/conversational-ai -> Create Agent
CLI (Agents as Code):
elevenlabs agents init
elevenlabs agents add "Support Bot" --template customer-service
# Edit agent_configs/support-bot.json
elevenlabs agents push --env dev
Templates: default, minimal, voice-only, text-only, customer-service, assistant.
Configure:
- Voice -- Choose from 5000+ voices or clone
- LLM -- GPT, Claude, Gemini, or custom
- System prompt -- Use the 6-component framework below
- First message -- What the agent says when conversation starts
Step 2: Write the System Prompt
Use the 6-component framework for effective agent prompts:
1. Personality -- who the agent is:
You are [NAME], a [ROLE] at [COMPANY].
You have [EXPERIENCE]. Your traits: [LIST TRAITS].
2. Environment -- communication context:
You're communicating via [phone/chat/video].
Consider [environmental factors]. Adapt to [context].
3. Tone -- speech patterns and formality:
Tone: Professional yet warm. Use contractions for natural speech.
Avoid jargon. Keep responses to 2-3 sentences. Ask one question at a time.
4. Goal -- objectives and success criteria:
Primary Goal: Resolve customer issues on the first call.
Success: Customer verbally confirms issue is resolved.
5. Guardrails -- boundaries and ethics:
Never: provide medical/legal/financial advice, share confidential info.
Always: verify identity before account access, document interactions.
Escalation: customer requests manager, issue beyond knowledge base.
6. Tools -- available functions and when to use them:
1. lookup_order(order_id) -- Use when customer mentions an order.
2. transfer_to_supervisor() -- Use when issue requires manager approval.
Always explain what you're doing before calling a tool.
Step 3: Add Tools
Client-side tools (run in browser):
const clientTools = {
updateCart: {
description: "Add or remove items from the shopping cart",
parameters: z.object({
action: z.enum(['add', 'remove']),
item: z.string(),
quantity: z.number().min(1)
}),
handler: async ({ action, item, quantity }) => {
const cart = getCart();
action === 'add' ? cart.add(item, quantity) : cart.remove(item, quantity);
return { success: true, total: cart.total, items: cart.items.length };
}
},
navigate: {
description: "Navigate user to a different page",
parameters: z.object({ url: z.string().url() }),
handler: async ({ url }) => { window.location.href = url; return { success: true }; }
}
};
Server-side tools (webhooks):
{
"name": "get_weather",
"description": "Fetch current weather for a city",
"url": "https://api.weather.com/v1/current",
"method": "GET",
"parameters": {
"type": "object",
"properties": {
"city": { "type": "string", "description": "City name" }
},
"required": ["city"]
},
"headers": {
"Authorization": "Bearer {{secret__weather_api_key}}"
}
}
Use {{secret__key_name}} for API keys in webhook headers -- never hardcode.
MCP Tools -- CRITICAL COMPATIBILITY NOTE:
ElevenLabs labels their MCP integration as "Streamable HTTP" but does NOT support the actual MCP 2025-03-26 Streamable HTTP spec (SSE responses). ElevenLabs expects:
- Plain JSON responses (
application/json), NOT SSE (text/event-stream) - Protocol version
2024-11-05, NOT2025-03-26 - Simple JSON-RPC over HTTP with direct JSON responses
What does NOT work:
- Official MCP SDK's
createMcpHandler(returns SSE) - Cloudflare Agents SDK
McpServer.serve()(returns SSE) - Any server returning
Content-Type: text/event-stream
Working MCP server pattern for ElevenLabs:
import { Hono } from 'hono';
import { cors } from 'hono/cors';
const tools = [{
name: "my_tool",
description: "Tool description",
inputSchema: {
type: "object",
properties: { param1: { type: "string", description: "Description" } },
required: ["param1"]
}
}];
async function handleMCPRequest(request, env) {
const { id, method, params } = request;
switch (method) {
case 'initialize':
return {
jsonrpc: '2.0', id,
result: {
protocolVersion: '2024-11-05', // MUST be 2024-11-05
serverInfo: { name: 'my-mcp', version: '1.0.0' },
capabilities: { tools: {} }
}
};
case 'tools/list':
return { jsonrpc: '2.0', id, result: { tools } };
case 'tools/call':
const result = await handleTool(params.name, params.arguments, env);
return { jsonrpc: '2.0', id, result };
default:
return { jsonrpc: '2.0', id, error: { code: -32601, message: `Unknown: ${method}` } };
}
}
const app = new Hono();
app.use('/*', cors({ origin: '*', allowMethods: ['GET', 'POST', 'OPTIONS'] }));
app.post('/mcp', async (c) => {
const body = await c.req.json();
return c.json(await handleMCPRequest(body, c.env)); // Plain JSON, NOT SSE
});
export default app;
Step 4: Add Knowledge Base (RAG)
Upload documents for the agent to reference:
- PDFs, text files, web URLs
- Configure via dashboard: Agent -> Knowledge Base -> Upload
- Or via API:
POST /v1/convai/knowledge-base/upload(multipart/form-data) - Agent automatically searches knowledge base during conversation
Step 5: Integrate SDK
React -- copy and customise assets/react-sdk-boilerplate.tsx:
import { useConversation } from '@elevenlabs/react';
const { startConversation, stopConversation, status } = useConversation({
agentId: 'your-agent-id',
signedUrl: '/api/elevenlabs/auth',
clientTools,
dynamicVariables: {
user_name: 'John',
account_type: 'premium',
},
onEvent: (event) => { /* transcript, agent_response, tool_call */ },
});
System prompt references dynamic variables as {{user_name}}.
React Native -- see assets/react-native-boilerplate.tsx
Widget embed -- see assets/widget-embed-template.html
Swift -- see assets/swift-sdk-boilerplate.swift
Step 6: Test
CLI testing:
# Run all tests for an agent
elevenlabs agents test "Support Agent"
# Add a test scenario
elevenlabs tests add "Refund Request" --template basic-llm
Test configuration:
{
"name": "Refund Request Test",
"scenario": "Customer requests refund for defective product",
"user_input": "I want a refund for order #12345. The product arrived broken.",
"success_criteria": [
"Agent acknowledges the issue empathetically",
"Agent asks for or uses provided order number",
"Agent verifies order details",
"Agent provides clear next steps or refund timeline"
],
"evaluation_type": "llm"
}
Tool call testing:
{
"name": "Order Lookup Test",
"scenario": "Customer asks about order status",
"user_input": "What's the status of order ORD-12345?",
"expected_tool_call": {
"tool_name": "lookup_order",
"parameters": { "order_id": "ORD-12345" }
}
}
API simulation:
const simulation = await client.agents.simulate({
agent_id: 'agent_123',
scenario: 'Customer requests refund',
user_messages: [
"I want a refund for order #12345",
"It arrived broken",
"Yes, process the refund"
],
success_criteria: [
"Agent shows empathy",
"Agent verifies order",
"Agent provides timeline"
]
});
console.log('Passed:', simulation.passed);
CI/CD integration:
name: Test Agent
on: [push, pull_request]
jobs:
test:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- run: npm install -g @elevenlabs/cli
- run: elevenlabs tests push
env:
ELEVENLABS_API_KEY: ${{ secrets.ELEVENLABS_API_KEY }}
- run: elevenlabs agents test "Support Agent"
env:
ELEVENLABS_API_KEY: ${{ secrets.ELEVENLABS_API_KEY }}
Step 7: Deploy
# Dry run first (always)
elevenlabs agents push --env prod --dry-run
# Deploy to production
elevenlabs agents push --env prod
Multi-environment workflow:
elevenlabs agents push --env dev # Development
elevenlabs agents push --env staging # Staging
elevenlabs agents test "Agent Name" # Test in staging
elevenlabs agents push --env prod # Production
Critical Patterns
Signed URLs (Security)
Never expose API keys in client code. Use a server endpoint:
app.get('/api/elevenlabs/auth', async (req, res) => {
const response = await fetch(
'https://api.elevenlabs.io/v1/convai/conversation/get-signed-url',
{
headers: { 'xi-api-key': process.env.ELEVENLABS_API_KEY },
body: JSON.stringify({ agent_id: 'your-agent-id' }),
method: 'POST'
}
);
const { signed_url } = await response.json();
res.json({ signed_url });
});
Agent Versioning (A/B Testing)
Dashboard: Agent -> Versions -> Create Branch. Compare metrics, promote winner.
Post-Call Webhook
{
"type": "post_call_transcription",
"data": {
"conversation_id": "conv_xyz789",
"transcript": "...",
"duration_seconds": 120,
"analysis": { "sentiment": "positive", "resolution": true }
}
}
Verify with HMAC SHA-256:
const hmac = crypto.createHmac('sha256', process.env.WEBHOOK_SECRET)
.update(JSON.stringify(request.body)).digest('hex');
if (signature !== hmac) { /* reject */ }
Cost Optimisation
| Model | Cost/1M tokens | Speed | Best For |
|---|---|---|---|
| GPT-4o | $5 | Medium | Complex reasoning |
| GPT-4o-mini | $0.15 | Fast | Most use cases |
| Claude Sonnet 4.5 | $3 | Medium | Long context |
| Gemini 2.5 Flash | $0.075 | Fastest | Simple tasks |
Start with gpt-4o-mini for all agents. Upgrade only if quality requires it.
Key savings:
- LLM caching: up to 90% on repeated prompts (enable in config)
- Prompt length: 150 tokens > 500 tokens for same instructions
- RAG over context: use knowledge base instead of stuffing system prompt
- Duration limits: set
max_duration_secondsto prevent runaway conversations - Turn mode: "patient" mode = fewer LLM calls = lower cost
CLI Quick Reference
elevenlabs auth login # Authenticate
elevenlabs agents init # Init project
elevenlabs agents add "Name" --template default # Add agent
elevenlabs agents push --env dev # Deploy to dev
elevenlabs agents push --env prod --dry-run # Preview prod deploy
elevenlabs agents push --env prod # Deploy to prod
elevenlabs agents pull # Pull from platform
elevenlabs agents test "Name" # Run tests
elevenlabs agents list # List agents
elevenlabs agents status # Check sync status
elevenlabs agents widget "Name" # Generate widget
elevenlabs tools add-webhook "Name" --config-path tool.json # Add tool
elevenlabs tests add "Name" --template basic-llm # Add test
Environment: ELEVENLABS_API_KEY for CI/CD.
Optional References
For specialised use cases, see:
references/api-reference.md-- full REST API for programmatic agent managementreferences/compliance-guide.md-- GDPR, HIPAA, PCI DSS, data residencyreferences/workflow-examples.md-- multi-agent routing, escalation, multi-language
Asset Files
assets/react-sdk-boilerplate.tsx-- React integration templateassets/react-native-boilerplate.tsx-- React Native templateassets/swift-sdk-boilerplate.swift-- Swift/iOS templateassets/javascript-sdk-boilerplate.js-- Vanilla JS templateassets/widget-embed-template.html-- Embeddable widgetassets/system-prompt-template.md-- System prompt guideassets/agent-config-schema.json-- Config schema referenceassets/ci-cd-example.yml-- CI/CD pipeline template
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