Tools & Functions

What is a Tool?

Tools are functions that the voice agent can call automatically during a conversation. Unlike workflow nodes that you configure manually, tools are used by the AI when it needs them.

You don’t need to trigger tools manually. Once a tool is available to the workflow - built in, enabled in workflow settings, or exposed by an active integration - the agent decides on its own when to use it. For custom HTTP tools, “available” means two things:

the tool is Active in the Integrations page
the tool is attached to a Start Call, Agent, or End Call node

For example, if a caller asks “How much is 1500 plus 800?”, the agent will automatically call the calculator.

Custom HTTP Tools

Custom HTTP tools let you call your own public HTTP endpoints during a conversation.

How to Use Them

Create the tool in Integrations > HTTP Tools
Keep the tool in Active status
Open your workflow builder
Attach the tool to a Start Call, Agent, or End Call node
Save the workflow

Creating a tool is not enough on its own. If the tool is not attached to a node, the AI cannot call it.

How Does It Work?

The agent:

Analyzes what the caller says
Detects that a tool would be useful
Calls the tool with the right parameters
Uses the result to respond naturally

Available Tools

Calculator

Real-time mathematical calculations

Timezone

Time and timezone conversions

Knowledge Base

Search your knowledge bases

Send SMS

Send SMS during the call

Google Calendar

Check availability and create appointments

Immofacile

Real estate property search

Zenchef

Restaurant reservations

Calculator

Allows the agent to perform mathematical calculations during the call.

When the Agent Uses It

“How much is 1500 plus 800?”
“If the rent is 950 euros, how much is that per year?”
“What’s the price per square meter for 250,000 euros on 85 sqm?”

Supported Operations

Operator	Description	Example
`+`	Addition	`2000 + 500`
`-`	Subtraction	`5000 - 1200`
`*`	Multiplication	`950 * 12`
`/`	Division	`250000 / 85`
`**`	Power	`2 ** 10`
`%`	Modulo (remainder)	`17 % 5`
`()`	Parentheses	`(100 + 50) * 2`

Example

Caller: "If the property is 320,000 euros and I put down 50,000,
         how much do I need to finance?"

Agent: [Calls calculator("320000 - 50000")]
       "You would need to finance 270,000 euros."

Timezone

Allows the agent to get the current time in different timezones and convert times.

When the Agent Uses It

“What time is it in New York?”
“If I call you at 2pm Paris time, what time will it be in Tokyo?”

Available Functions

Function	Description
`get_current_time`	Get current time in a timezone
`convert_time`	Convert time from one timezone to another

Timezone Format

The agent uses IANA format (international standard):

Location	IANA Code
France	`Europe/Paris`
New York	`America/New_York`
Los Angeles	`America/Los_Angeles`
London	`Europe/London`
Tokyo	`Asia/Tokyo`
Sydney	`Australia/Sydney`
Dubai	`Asia/Dubai`

Example

Caller: "If we schedule a call at 3pm Paris time,
         what time will it be in New York?"

Agent: [Calls convert_time("Europe/Paris", "15:00", "America/New_York")]
       "At 3pm Paris time, it will be 9am in New York.
        Does that work for you?"

Knowledge Base (RAG)

Allows the agent to search for information in your knowledge bases.

The agent has automatic access to all knowledge bases in your organization. You don’t need to specify which one to use.

When the Agent Uses It

Questions about your products or services
Checking internal policies
Looking up technical information
FAQ and common questions

How It Works

The agent detects a question requiring specific information
It formulates a search query
The system searches all your knowledge bases
The agent receives the most relevant passages
It uses this information to respond

Example

Caller: "What are your opening hours on Saturday?"

Agent: [Calls search_knowledge_base("opening hours Saturday")]
       "According to our information, we're open on Saturdays
        from 9am to 12:30pm. Would you like to schedule an appointment?"

Send SMS

Allows the agent to send an SMS during the call.

This feature must be enabled in the workflow configuration to be available.

When the Agent Uses It

Send an appointment summary
Share a confirmation link
Provide contact information

Parameters

Parameter	Description
`recipient_phone`	Recipient’s phone number
`message`	SMS content (160 characters max for a single SMS)

Activation

To enable SMS sending in a workflow:

Open the workflow settings
Enable the “Send SMS” option
Configure the sender name

Example

Agent: "I'll send you an SMS with your appointment summary."

       [Calls send_sms("+33612345678", "Appointment confirmed: Monday 15th at 2pm")]

       "Done! You should receive it in a few moments."

Integrations (Advanced Tools)

These tools require an integration configured in your account.

Google Calendar

Check availability and create appointments in Google Calendar.

Google Calendar Guide

Configuration and usage of the Google Calendar integration

Immofacile

Real-time property search for real estate agencies.

Immofacile Guide

Configuration and usage of the Immofacile integration

Zenchef

Check availability and make reservations at restaurants using Zenchef.

Zenchef Guide

Configuration and usage of the Zenchef integration

Zelty

Browse menus, create orders, and check order status during restaurant calls. Once the Zelty integration is active, these tools are available automatically.

Zelty Guide

Configuration and usage of the Zelty integration

Stripe (Paiement)

Send Stripe payment links by SMS during live calls. Once Stripe is active, the generic payment link tool is available automatically. If both Zelty and Stripe are active, the combined order + payment flow is exposed automatically as well.

Stripe Guide

Configuration and usage of the Stripe payment integration

Custom HTTP Tools

Beyond the built-in tools listed above, you can create your own custom HTTP tools that the AI agent calls during conversations. This lets the agent interact with any external API — your CRM, booking system, inventory service, or any other HTTP endpoint.

How It Works

A custom HTTP tool works just like a built-in tool: the AI agent decides when to call it based on the conversation context. The difference is that instead of calling an internal function, it sends an HTTP request to an endpoint you define.

Creating a Custom Tool

Go to the Integrations page in your dashboard
Click Add Custom Tool
Fill in the configuration fields shown in the dialog
Click Save

Configuration

Field	Description
Name	A short, descriptive name the AI uses to identify the tool (e.g., “Check Inventory”)
Description	A clear explanation of what the tool does and when to use it. The AI reads this to decide when to call the tool
HTTP Method	`GET`, `POST`, `PUT`, `PATCH`, or `DELETE`
URL	The endpoint to call
Timeout	Request timeout in milliseconds
Parameters	Input parameters the AI extracts from the conversation and passes to the tool

Parameters

Parameters define what information the AI should extract from the conversation to pass to the tool. Each parameter has:

Property	Description
Name	Parameter identifier (e.g., `sku`, `customer_email`)
Type	Data type (`string`, `number`, `boolean`)
Description	What this parameter represents (helps the AI extract the right value)
Required	Whether the AI must collect this value before calling the tool

Request Behavior

POST, PUT, and PATCH requests send the tool arguments as a JSON body
GET and DELETE requests send the tool arguments as query parameters
Non-2xx responses are surfaced to Tala as tool errors instead of success responses

Advanced Configuration

The current create/edit dialog focuses on the fields above. Tala also supports additional advanced options at the platform/API layer:

Static HTTP headers
Stored credentials for authentication

These advanced fields are not yet exposed in the current custom tool form.

Testing

After saving a tool, use the Test action from the tools list to run the current configuration and inspect the response. Tala shows the returned result, and HTTP error responses are displayed as errors.

The description field is critical. The AI uses it to decide when to call the tool. Write it as if you were explaining to a colleague when and why they should use this endpoint.

Best Practices

Test with Looptalk - Before going live, test your workflows with Looptalk to verify that tools work correctly.

Trust the agent - The agent knows when to use tools. You don’t need to explicitly tell it in the prompt.

Keep your knowledge bases updated - The more complete your KBs, the more accurately the agent can answer questions.

Plan for no-result cases - Tools may sometimes return no results. The agent can handle these situations, but you can add instructions in the prompt to guide its behavior.

​What is a Tool?

​Custom HTTP Tools

​How to Use Them

​How Does It Work?

​Available Tools

Calculator

Timezone

Knowledge Base

Send SMS

Google Calendar

Immofacile

Zenchef

​Calculator

​When the Agent Uses It

​Supported Operations

​Example

​Timezone

​When the Agent Uses It

​Available Functions

​Timezone Format

​Example

​Knowledge Base (RAG)

​When the Agent Uses It

​How It Works

​Example

​Send SMS

​When the Agent Uses It

​Parameters

​Activation

​Example

​Integrations (Advanced Tools)

​Google Calendar

Google Calendar Guide

​Immofacile

Immofacile Guide

​Zenchef

Zenchef Guide

​Zelty

Zelty Guide

​Stripe (Paiement)

Stripe Guide

​Custom HTTP Tools

​How It Works

​Creating a Custom Tool

​Configuration

​Parameters

​Request Behavior

​Advanced Configuration

​Testing

​Best Practices

What is a Tool?

Custom HTTP Tools

How to Use Them

How Does It Work?

Available Tools

Calculator

When the Agent Uses It

Supported Operations

Example

Timezone

When the Agent Uses It

Available Functions

Timezone Format

Example

Knowledge Base (RAG)

When the Agent Uses It

How It Works

Example

Send SMS

When the Agent Uses It

Parameters

Activation

Example

Integrations (Advanced Tools)

Google Calendar

Immofacile

Zenchef

Zelty

Stripe (Paiement)

Custom HTTP Tools

How It Works

Creating a Custom Tool

Configuration

Parameters

Request Behavior

Advanced Configuration

Testing

Best Practices