Native Functions | SignalWire

What Are Native Functions?

Native functions run directly on SignalWire’s platform. Enable them to give the AI access to built-in capabilities without creating handlers.

Handler Function	Native Function
You define handler	SignalWire provides
Runs on your server	Runs on SignalWire
Custom logic	Pre-built behavior

Available Native Functions:

web_search - Search the web
debug - Debug mode for testing

Enabling Native Functions

Enable native functions in the constructor. The syntax varies by language:

Language	Syntax
Python	`AgentBase(name="my-agent", native_functions=["web_search"])`
TypeScript	`new AgentBase({ name: 'my-agent', nativeFunctions: ['web_search'] })`

from signalwire import AgentBase
class MyAgent(AgentBase):
    def __init__(self):
        super().__init__(
            name="my-agent",
            native_functions=["web_search"]  # Enable web search
        )
        self.add_language("English", "en-US", "rime.spore")

Web Search Function

Enable web search to let the AI autonomously search the web during conversations:

class ResearchAgent(AgentBase):
    def __init__(self):
        super().__init__(
            name="research-agent",
            native_functions=["web_search"]
        )
        self.add_language("English", "en-US", "rime.spore")
        self.prompt_add_section(
            "Role",
            "You are a research assistant. Search the web to answer questions."
        )

How Web Search Works

When enabled, the AI can decide to search the web when it needs information to answer a question. The process is:

AI decides to search: Based on the conversation, the AI determines a search is needed
Query formulation: The AI creates a search query from the conversation context
Search execution: SignalWire executes the search on the AI’s behalf
Results processing: Search results are returned to the AI as context
Response generation: The AI synthesizes the results into a spoken response

The caller doesn’t interact with search directly — the AI handles everything automatically.

What Web Search Returns

The AI receives search results including:

Page titles and snippets
URLs of matching pages
Relevant text excerpts

The AI then summarizes and presents this information conversationally. It doesn’t read URLs or raw HTML to the caller.

Web Search Limitations

No control over search behavior:

Cannot specify search engine (Google, Bing, etc.)
Cannot filter by domain or site
Cannot control result count
Cannot exclude specific sources

Content limitations:

Results may be outdated (search index lag)
Cannot access paywalled or login-required content
Cannot search private/internal sites
May not find very recent information

No result logging:

Search queries aren’t logged to your server
Cannot audit what was searched
Cannot cache results for reuse

Rate and cost:

Subject to SignalWire’s rate limits
May incur additional usage costs
Multiple searches per call add latency

When to Use Native web_search

Good use cases:

General knowledge questions (“What year was the Eiffel Tower built?”)
Current events (with freshness caveats)
Quick fact lookups during calls
Agents that need broad knowledge access

When to use alternatives instead:

Need	Alternative
Specific search engine	`web_search` skill with Google API
Domain-restricted search	Custom handler with filtered API
Result logging/auditing	Custom handler with logging
Cached results	Custom handler with caching layer
Internal/private content	Custom handler with your search backend

Prompting for Web Search

Guide the AI on when and how to use web search:

self.prompt_add_section(
    "Search Guidelines",
    """
    Use web search when:
    - Asked about current events or recent information
    - Need to verify facts you're uncertain about
    - Question is outside your core knowledge
    Don't search for:
    - Information already in your prompt
    - Customer-specific data (use account functions instead)
    - Simple calculations or conversions
    """
)

Debug Function

Enable debug mode for development and testing:

class DebugAgent(AgentBase):
    def __init__(self):
        super().__init__(
            name="debug-agent",
            native_functions=["debug"]
        )
        self.add_language("English", "en-US", "rime.spore")

What Debug Provides

The debug function exposes diagnostic information during calls:

Current conversation state
Function call history
Configuration details
Timing information

When to Use Debug

Use during development:

Testing conversation flows
Verifying function registration
Checking prompt configuration
Troubleshooting unexpected behavior

Don’t use in production:

Exposes internal details to callers
May reveal sensitive configuration
Adds unnecessary function to AI’s options
Remove before deploying to production

Call Transfers

For call transfers, use FunctionResult.connect() in a custom handler function - there is no native transfer function:

from signalwire import AgentBase, FunctionResult
class TransferAgent(AgentBase):
    DEPARTMENTS = {
        "sales": "+15551111111",
        "support": "+15552222222",
        "billing": "+15553333333"
    }
    def __init__(self):
        super().__init__(name="transfer-agent")
        self.add_language("English", "en-US", "rime.spore")
        self.prompt_add_section(
            "Role",
            "You are a receptionist. Transfer callers to the appropriate department."
        )
        self.define_tool(
            name="transfer_call",
            description="Transfer the call to a department",
            parameters={
                "type": "object",
                "properties": {
                    "department": {
                        "type": "string",
                        "description": "Department to transfer to",
                        "enum": ["sales", "support", "billing"]
                    }
                },
                "required": ["department"]
            },
            handler=self.transfer_call
        )
    def transfer_call(self, args, raw_data):
        department = args.get("department")
        number = self.DEPARTMENTS.get(department)
        if not number:
            return FunctionResult("Invalid department")
        return (
            FunctionResult(f"Transferring you to {department}")
            .connect(number, final=True)
        )

Combining Native and Custom Functions

The examples below use Python. The pattern of passing native_functions in the constructor and adding define_tool() calls works identically in all SDK languages using the syntax shown in the table above.

Use native functions alongside your custom handlers:

from signalwire import AgentBase, FunctionResult
class HybridAgent(AgentBase):
    def __init__(self):
        super().__init__(
            name="hybrid-agent",
            native_functions=["web_search"]  # Native
        )
        self.add_language("English", "en-US", "rime.spore")
        # Custom function alongside native ones
        self.define_tool(
            name="check_account",
            description="Look up customer account information",
            parameters={
                "type": "object",
                "properties": {
                    "account_id": {
                        "type": "string",
                        "description": "Account ID"
                    }
                },
                "required": ["account_id"]
            },
            handler=self.check_account
        )
        self.prompt_add_section(
            "Role",
            "You are a customer service agent. "
            "You can check accounts and search the web for information."
        )
    def check_account(self, args, raw_data):
        account_id = args.get("account_id")
        return FunctionResult(f"Account {account_id} is active")

When to Use Native vs Custom Functions

Scenario	Recommendation
Web search capability	Use `web_search` native function
Development testing	Use `debug` native function
Transfer to phone number	Use FunctionResult.connect() in custom handler
Transfer to SIP address	Use FunctionResult.connect() in custom handler
Custom business logic	Use define_tool() with handler
Database lookups	Use define_tool() with handler

Native Functions Reference

Function	Description	Use Case
`web_search`	Search the web	Answer general questions
`debug`	Debug information	Development/testing

Next Steps

You’ve now learned all about SWAIG functions. Next, explore Skills to add pre-built capabilities to your agents.