Function calls allow the agent to perform real actions such as booking appointments or transferring calls.Documentation Index
Fetch the complete documentation index at: https://docs.sigmamind.ai/llms.txt
Use this file to discover all available pages before exploring further.

- Voice Tool
- Extract Variables
- Integration Tool
Voice Tool Calls
Voice Tool Calls allow the agent to control the call flow, such as transferring the call to a human agent or ending the call programmatically.
- Click Add tool
- Select Voice Tool Call
- Select Action
- ivr_navigator
- voice_transfer_call
- voice_end_call
- Configure the required fields
- Click Add to Agent to save the tool configuration
- ivr_navigator
- voice_transfer_call
- voice_end_call
IVR Navigator
Enable your AI agent to navigate IVR systems and make outbound calls like a human caller. The agent sends keypad inputs (DTMF) when required, responds naturally when prompted for speech, and seamlessly continues the interaction if a human agent joins.
How It Works
When an outbound call is placed, the receiving system may respond with:- A traditional IVR menu
- A conversational AI system
- A live human agent
- Or a combination of all three
Press vs. Say
- If the IVR says “Press 1 for English”
→ The agent sends a keypad digit using IVR Navigator - If the IVR says “Say 1” or asks a question
→ The agent responds using normal speech
Supported IVR Types
Press-type”Press 1 for X, Press 2 for Y”
→ IVR Navigator is triggered Say-type
”Say 1 for English” or open-ended prompts
→ Handled via normal speech (no tool call) Conversational AI
Acts like a human and asks questions
→ IVR Navigator is used only if numeric input is explicitly required Mixed (IVR + Human)
IVR transitions to a human and may return to keypad input
→ IVR Navigator is triggered only for digit-based steps
How to Configure
Step 1: In Agent Builder, go to Add Tool Step 2: Select the Voice Tool and addivr_navigator as a tool.
Step 3: Add a Description to define when the agent should trigger ivr_navigator.
Recommended:Always call this tool only when the IVR explicitly asks for numeric input (e.g., “press” or “enter” a digit/number).
Do NOT call this method for spoken responses or unclear prompts. Step 4: Set IVR starts conversation? (Yes / No)
Specify whether the IVR system begins speaking at the start of the call.
- Yes → Use this when the call starts with an IVR greeting or menu.
The agent will wait for the configured Pause Delay before processing, ensuring the full message is received. - No → Use this when no initial IVR delay handling is needed.
The agent will begin processing immediately.
Defines how long (in milliseconds) the agent waits after IVR speech before taking action. IVR systems often deliver menu options in fragments with short pauses. Without a delay, the agent may act too early. Recommended: 2000 ms Step 4: Click on Add to Agent Useful for workflows that prioritize connecting only to human agents.

Step 4: Write your agent system prompt
All navigation logic, goals, and behavioral constraints should be defined in the agent’s system prompt.Agent Prompt Guide
Define the goal
Clearly specify what the agent must achieve. Example:Navigate the IVR system, retrieve required information, complete necessary inputs, and connect to a human agent if needed.
Provide a navigation path (recommended)
If the IVR structure is known, include the expected flow. This significantly improves reliability. Example:- Select language
- Select account type
- Select service category
- Proceed to the target function
Pass caller data as dynamic variables
Provide structured data that the agent may need during the call:- Mobile number
- Reference or account number
- Policy or claim ID
- Verification details (e.g., last 4 digits of SSN)
It should not act as a support representative or provide solutions, explanations, or guidance.
Behavioral Guidelines
To ensure reliable IVR navigation:- Only act when input is explicitly requested
- Do not respond to informational (e.g., hold music, “please wait”)
- Do not guess or assume menu options
- Do not press fallback keys (e.g., 0 or 9) unless explicitly instructed
- Separate digit input actions from spoken responses
Example prompt:
Voice Transfer Call
The Voice Transfer Call action allows the agent to transfer an active call to another agent, team, or phone number when escalation or human assistance is required. This ensures a smooth handoff experience by optionally sharing conversation context with the receiving agent before connecting the user.Use this action when:
- The user asks to speak with a human agent
- The request requires human intervention
- The conversation needs escalation to a specialist
- The workflow requires routing to another department (Sales, Support, Billing, etc.)
How to Configure
Step 1: Select Action
The Select the action dropdown allows you to choose which voice function the agent should perform. Select: voice_transfer_call
Step 2: Transfer To
Defines where the call will be transferred.
The transfer phone number must be entered in E.164 international format, including the country code.
Step 3: Transfer Types
SigmaMind provides two transfer types: Cold Transfer for immediate routing and Warm Transfer for assisted handoff with context.
Cold Transfer
Cold transfer immediately connects the caller to the destination number. Behavior:- AI transfers the call and exits the conversation
- No context is shared with the receiving agent
- Caller hears ringing and connects directly
- Context is not required
- Simple routing to support or department
- Fast escalation is needed
Warm Transfer
Warm transfer connects the receiving agent first, shares context, and then bridges the caller. This provides a smoother and more professional experience. Warm transfer includes two stages: Connecting Stage and Bridged Stage
Stage 1: Connecting Stage
The receiving agent is connected, but the user is still on hold.Whisper Message
A private message played only to the receiving agent. The user cannot hear this message. You can configure this as Static or Prompt.
- Turn the Whisper Message toggle ON
- Enter the message in the text box
- Choose either:
- Static – fixed message, or
- Prompt – dynamically generated message using variables
Static Whisper Message Example
Prompt Whisper Message Example
Prompt messages are generated dynamically based on conversation context. Instead of sending fixed text, you provide instructions, and SigmaMind AI automatically creates a contextual summary for the receiving agent. Prompt example configuration:If the whisper message is left empty, the transfer will still proceed, but no context will be shared. In this case, the warm transfer effectively behaves like a cold transfer.
Stage 2: Bridged Stage
The Bridged Stage is the phase in a Warm Transfer where the caller and the human agent are fully connected and can speak to each other directly. At this stage, the transfer is complete, and the conversation moves from the AI agent to the human agent. You can optionally enable a Three-way Message to announce the connection and ensure a smooth and professional transition for both participants. The Three-way Message allows the AI agent to play a message to both the caller and the human agent after the call is connected.
- Turn the Three-way Message toggle ON
- Enter the message in the text box
- Choose either:
- Static – fixed announcement message, or
- Prompt – dynamically generated message using variables
Step 4: Custom Headers(Optional)
Custom Headers allow you to send structured metadata along with the call transfer.These headers are invisible to the customer but available to

- Receiving agents
- CRM systems
- Call center software
- Backend systems
Headers provide structured context for automation and reporting.
How Custom Headers Work Headers are sent as key-value pairs.
Step 5: Click Add to Agent
If the agent does not answer or the transfer fails due to network issues, SigmaMind automatically retries the transfer based on the configured settings.
Execution Flow
Best Practices
- Use Warm Transfer for better customer experience
- Use Prompt Whisper Message to provide dynamic context
- Keep messages clear and concise
- Use dynamic variables for intelligent routing
- Provide useful context to receiving agents
Voice End Call
This function allows the agent to end the call automatically when the conversation is complete or the user no longer needs assistance. This ensures a clean and professional call termination without requiring manual intervention.
- Click Add tool
- Select Voice Tool Call
- Select Tool → voice_end_call
- Click Add to Agent
- Conversation is complete
- Task or request has been successfully finished
- User confirms no further help is needed
- User says goodbye or wants to end the call
- User is frustrated or does not want to continue
- Call needs to be terminated gracefully
Extract Variables
Extract Variables allow the agent to capture and store important information from the conversation, such as customer name, phone number, or appointment details. Please note that this is useful when the call and chat are still going on, and it has not yet completed.
- Click Add tool
- Select Extract Variable
- Configure the required fields
- Click Add to Agent to save the tool configuration
Integration Tool
Integration Tool Calls allow the agent to interact with external applications such as booking systems, CRM, or databases. Use App Tool Calls when the agent needs to fetch data, create records, or perform actions outside the conversation.
- Click Add Tool Call
- Select Integration Tool
- Choose the App
- Select the tool (function to call)
- Add a Description to define when the function should be called(optional)
- Click Add to Agent
- get_available_slots
- book_appointment
- update_crm
Function Description Field (Optional)
Each function includes a Description (When to call this function) field.