Voice Agents

Agent CRUD Examples

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Voice Agent Management Examples

Examples for creating, reading, updating, and deleting voice agents.

Create an Agent

JavaScript/TypeScript

Code
 
const API_KEY = "your-api-key";
const BASE_URL = "https://api.slng.ai";

async function createAgent() {
  const response = await fetch(`${BASE_URL}/v1/agents`, {
    method: "POST",
    headers: {
      Authorization: `Bearer ${API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      name: "Sales Outreach Agent",
      system_prompt: `You are a friendly sales representative for {{company_name}}.
You're calling to introduce our {{product_name}} to potential customers.

Guidelines:
- Be enthusiastic but not pushy
- Focus on benefits, not features
- Ask qualifying questions
- If interested, offer to send more information
- Keep calls under 5 minutes`,
      greeting:
        "Hi! This is Alex from {{company_name}}. Do you have a quick moment to chat?",
      language: "en",
      models: {
        stt: "deepgram/nova:2",
        llm: "openai/gpt-4o-mini",
        tts: "deepgram/aura:2",
        tts_voice: "aura-2-andromeda-en",
        llm_kwargs: { temperature: 0.8 },
      },
      enable_interruptions: true,
      tools: [
        { type: "template", template: "hangup" },
        { type: "template", template: "voicemail_detection" },
      ],
      slng_api_key: "your-slng-api-key",
      livekit_deployment: "production",
      template_defaults: {
        company_name: "TechStartup Inc",
        product_name: "CloudSync Pro",
      },
    }),
  });

  if (!response.ok) {
    const error = await response.json();
    throw new Error(`Failed to create agent: ${error.error}`);
  }

  return response.json();
}

// Usage
const agent = await createAgent();
console.log(`Created agent: ${agent.id}`);

Python

Code
 
import requests

API_KEY = "your-api-key"
BASE_URL = "https://api.slng.ai"

def create_agent():
    response = requests.post(
        f"{BASE_URL}/v1/agents",
        headers={
            "Authorization": f"Bearer {API_KEY}",
            "Content-Type": "application/json"
        },
        json={
            "name": "Sales Outreach Agent",
            "system_prompt": """You are a friendly sales representative for {{company_name}}.
You're calling to introduce our {{product_name}} to potential customers.

Guidelines:
- Be enthusiastic but not pushy
- Focus on benefits, not features
- Ask qualifying questions
- If interested, offer to send more information
- Keep calls under 5 minutes""",
            "greeting": "Hi! This is Alex from {{company_name}}. Do you have a quick moment to chat?",
            "language": "en",
            "models": {
                "stt": "deepgram/nova:2",
                "llm": "openai/gpt-4o-mini",
                "tts": "deepgram/aura:2",
                "tts_voice": "aura-2-andromeda-en",
                "llm_kwargs": {"temperature": 0.8}
            },
            "enable_interruptions": True,
            "tools": [
                {"type": "template", "template": "hangup"},
                {"type": "template", "template": "voicemail_detection"}
            ],
            "slng_api_key": "your-slng-api-key",
            "livekit_deployment": "production",
            "template_defaults": {
                "company_name": "TechStartup Inc",
                "product_name": "CloudSync Pro"
            }
        }
    )
    response.raise_for_status()
    return response.json()

# Usage
agent = create_agent()
print(f"Created agent: {agent['id']}")

cURL

Code
 
curl -X POST https://api.slng.ai/v1/agents \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Sales Outreach Agent",
    "system_prompt": "You are a friendly sales representative...",
    "greeting": "Hi! This is Alex from {{company_name}}.",
    "language": "en",
    "models": {
      "stt": "deepgram/nova:2",
      "llm": "openai/gpt-4o-mini",
      "tts": "deepgram/aura:2",
      "tts_voice": "aura-2-andromeda-en"
    },
    "slng_api_key": "your-slng-api-key",
    "livekit_deployment": "production"
  }'

List All Agents

JavaScript/TypeScript

Code
 
async function listAgents() {
  const response = await fetch(`${BASE_URL}/v1/agents`, {
    headers: {
      Authorization: `Bearer ${API_KEY}`,
    },
  });

  if (!response.ok) {
    throw new Error("Failed to list agents");
  }

  return response.json();
}

// Usage
const agents = await listAgents();
console.log(`Found ${agents.length} agents:`);
agents.forEach((agent) => {
  console.log(`- ${agent.name} (${agent.id})`);
});

Python

Code
 
def list_agents():
    response = requests.get(
        f"{BASE_URL}/v1/agents",
        headers={"Authorization": f"Bearer {API_KEY}"}
    )
    response.raise_for_status()
    return response.json()

# Usage
agents = list_agents()
print(f"Found {len(agents)} agents:")
for agent in agents:
    print(f"- {agent['name']} ({agent['id']})")

Get a Single Agent

JavaScript/TypeScript

Code
 
async function getAgent(agentId) {
  const response = await fetch(`${BASE_URL}/v1/agents/${agentId}`, {
    headers: {
      Authorization: `Bearer ${API_KEY}`,
    },
  });

  if (response.status === 404) {
    return null;
  }

  if (!response.ok) {
    throw new Error("Failed to get agent");
  }

  return response.json();
}

// Usage
const agent = await getAgent("550e8400-e29b-41d4-a716-446655440000");
if (agent) {
  console.log(`Agent: ${agent.name}`);
  console.log(`Models: STT=${agent.models.stt}, LLM=${agent.models.llm}`);
  console.log(`Template variables:`, agent.template_variables);
}

Python

Code
 
def get_agent(agent_id):
    response = requests.get(
        f"{BASE_URL}/v1/agents/{agent_id}",
        headers={"Authorization": f"Bearer {API_KEY}"}
    )
    if response.status_code == 404:
        return None
    response.raise_for_status()
    return response.json()

# Usage
agent = get_agent("550e8400-e29b-41d4-a716-446655440000")
if agent:
    print(f"Agent: {agent['name']}")
    print(f"Models: STT={agent['models']['stt']}, LLM={agent['models']['llm']}")

Update an Agent (Partial)

Use PATCH to update specific fields without replacing the entire agent.

JavaScript/TypeScript

Code
 
async function updateAgent(agentId, updates) {
  const response = await fetch(`${BASE_URL}/v1/agents/${agentId}`, {
    method: "PATCH",
    headers: {
      Authorization: `Bearer ${API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify(updates),
  });

  if (!response.ok) {
    const error = await response.json();
    throw new Error(`Failed to update agent: ${error.error}`);
  }

  return response.json();
}

// Update just the greeting
const updated = await updateAgent("550e8400-e29b-41d4-a716-446655440000", {
  greeting: "Hello! Thank you for your time today.",
});

// Update models configuration
const updated2 = await updateAgent("550e8400-e29b-41d4-a716-446655440000", {
  models: {
    stt: "deepgram/nova:2",
    llm: "openai/gpt-4o", // Upgraded from gpt-4o-mini
    tts: "elevenlabs/eleven-flash:2.5",
    tts_voice: "rachel",
    llm_kwargs: { temperature: 0.7 },
  },
});

// Add a webhook tool
const updated3 = await updateAgent("550e8400-e29b-41d4-a716-446655440000", {
  tools: [
    { type: "template", template: "hangup" },
    {
      type: "webhook",
      name: "schedule_callback",
      description: "Schedule a callback for the customer",
      url: "https://api.yourcompany.com/callbacks",
      parameters: {
        type: "object",
        properties: {
          preferred_time: {
            type: "string",
            description: "Preferred callback time",
          },
          phone_number: {
            type: "string",
            description: "Phone number to call back",
          },
        },
        required: ["preferred_time"],
      },
    },
  ],
});

Python

Code
 
def update_agent(agent_id, updates):
    response = requests.patch(
        f"{BASE_URL}/v1/agents/{agent_id}",
        headers={
            "Authorization": f"Bearer {API_KEY}",
            "Content-Type": "application/json"
        },
        json=updates
    )
    response.raise_for_status()
    return response.json()

# Update greeting
updated = update_agent("550e8400-e29b-41d4-a716-446655440000", {
    "greeting": "Hello! Thank you for your time today."
})

# Update template defaults
updated = update_agent("550e8400-e29b-41d4-a716-446655440000", {
    "template_defaults": {
        "company_name": "New Company Name",
        "product_name": "New Product"
    }
})

Replace an Agent (Full)

Use PUT to completely replace an agent configuration. All required fields must be provided.

JavaScript/TypeScript

Code
 
async function replaceAgent(agentId, agentConfig) {
  const response = await fetch(`${BASE_URL}/v1/agents/${agentId}`, {
    method: "PUT",
    headers: {
      Authorization: `Bearer ${API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify(agentConfig),
  });

  if (!response.ok) {
    const error = await response.json();
    throw new Error(`Failed to replace agent: ${error.error}`);
  }

  return response.json();
}

// Full replacement - all required fields must be provided
const replaced = await replaceAgent("550e8400-e29b-41d4-a716-446655440000", {
  name: "Sales Outreach Agent v2",
  system_prompt: "New and improved system prompt...",
  greeting: "New greeting!",
  language: "en",
  models: {
    stt: "deepgram/nova:2",
    llm: "openai/gpt-4o",
    tts: "elevenlabs/eleven-flash:2.5",
    tts_voice: "rachel",
  },
  slng_api_key: "your-slng-api-key",
  livekit_deployment: "production",
});

Delete an Agent

JavaScript/TypeScript

Code
 
async function deleteAgent(agentId) {
  const response = await fetch(`${BASE_URL}/v1/agents/${agentId}`, {
    method: "DELETE",
    headers: {
      Authorization: `Bearer ${API_KEY}`,
    },
  });

  if (response.status === 204) {
    return true; // Successfully deleted
  }

  if (response.status === 404) {
    return false; // Agent not found
  }

  throw new Error("Failed to delete agent");
}

// Usage
const deleted = await deleteAgent("550e8400-e29b-41d4-a716-446655440000");
if (deleted) {
  console.log("Agent deleted successfully");
}

Python

Code
 
def delete_agent(agent_id):
    response = requests.delete(
        f"{BASE_URL}/v1/agents/{agent_id}",
        headers={"Authorization": f"Bearer {API_KEY}"}
    )
    return response.status_code == 204

# Usage
if delete_agent("550e8400-e29b-41d4-a716-446655440000"):
    print("Agent deleted successfully")

Agent with Webhook Tools

Complete example of an agent with custom webhook integrations:

Code
 
const agentWithWebhooks = await createAgent({
  name: "Customer Service Agent",
  system_prompt: `You are a customer service agent for {{company_name}}.
You can look up order status, process returns, and escalate issues.

Available actions:
- Use check_order to look up order status
- Use process_return to initiate a return
- Use escalate_ticket to escalate to a human agent

Always verify the customer's identity before accessing their information.`,
  greeting:
    "Thank you for calling {{company_name}} support. How can I help you today?",
  language: "en",
  models: {
    stt: "deepgram/nova:2",
    llm: "openai/gpt-4o",
    tts: "deepgram/aura:2",
    tts_voice: "aura-2-andromeda-en",
  },
  tools: [
    { type: "template", template: "hangup" },
    {
      type: "webhook",
      name: "check_order",
      description: "Look up the status of a customer order",
      url: "https://api.yourcompany.com/orders/lookup",
      parameters: {
        type: "object",
        properties: {
          order_id: { type: "string", description: "The order ID" },
          customer_email: {
            type: "string",
            description: "Customer email for verification",
          },
        },
        required: ["order_id", "customer_email"],
      },
      auth: { type: "bearer", token: process.env.ORDERS_API_TOKEN },
      timeout_seconds: 10,
    },
    {
      type: "webhook",
      name: "process_return",
      description: "Initiate a return for an order",
      url: "https://api.yourcompany.com/returns/create",
      parameters: {
        type: "object",
        properties: {
          order_id: { type: "string" },
          reason: {
            type: "string",
            enum: ["defective", "wrong_item", "changed_mind", "other"],
          },
          notes: { type: "string" },
        },
        required: ["order_id", "reason"],
      },
      auth: { type: "bearer", token: process.env.RETURNS_API_TOKEN },
    },
    {
      type: "webhook",
      name: "escalate_ticket",
      description: "Escalate the issue to a human agent",
      url: "https://api.yourcompany.com/tickets/escalate",
      parameters: {
        type: "object",
        properties: {
          summary: {
            type: "string",
            description: "Brief summary of the issue",
          },
          priority: {
            type: "string",
            enum: ["low", "medium", "high", "urgent"],
          },
          customer_phone: { type: "string" },
        },
        required: ["summary", "priority"],
      },
      auth: { type: "hmac", secret: process.env.TICKETS_HMAC_SECRET },
      wait_for_response: false, // Fire and forget
    },
  ],
  slng_api_key: process.env.SLNG_API_KEY,
  livekit_deployment: "production",
  template_defaults: {
    company_name: "Acme Store",
  },
});

Error Handling

Code
 
async function safeCreateAgent(config) {
  try {
    const response = await fetch(`${BASE_URL}/v1/agents`, {
      method: "POST",
      headers: {
        Authorization: `Bearer ${API_KEY}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify(config),
    });

    if (response.status === 400) {
      const error = await response.json();
      console.error("Validation error:", error.error);
      return null;
    }

    if (response.status === 403) {
      console.error("Authentication failed - check your API key");
      return null;
    }

    if (response.status === 409) {
      console.error("Agent name already exists");
      return null;
    }

    if (!response.ok) {
      console.error("Unexpected error:", response.status);
      return null;
    }

    return response.json();
  } catch (error) {
    console.error("Network error:", error.message);
    return null;
  }
}