DialNexa Custom Functions

Configure DialNexa custom functions with API endpoints, authentication, parameters, JSON schemas, timeouts, and response variables.

DialNexa custom functions let an agent call your external API during a conversation. Use a custom function when the agent needs live data or needs to create something in a system that is not already handled by a dashboard integration.

A custom function turns a conversation into an integration. That is useful, and also a reason to test like you mean it.

Custom Function Fields

Each field changes how the agent calls the external service.

Field	Purpose
Description	Tells the model when and why to use the function.
API Endpoint	The URL of the service the function calls.
HTTP Method	The request method used by the function.
API Token	Optional bearer-style credential for the target API.
Timeout	Maximum wait time in milliseconds. The default reducer value is 120000.
Headers	Additional key-value headers.
Query Parameters	Key-value values appended to the URL.
Response Variables	Named values the agent can use after the API response.
JSON Schema	Defines the format the model should return for function arguments.

Use dashboard integrations when the action is available as a managed provider connection. Use a custom function when you own the API contract, need custom authentication, or need response variables from your own service during the call.

Dynamic Authorization For Chained API Calls

Custom function authentication can use values returned or supplied during the same tool call flow. This is useful when one function obtains a token and a later function must send that token to another API.

Pattern	Behavior
Static API token	Saved token is sent as Authorization when no custom header already sets it.
Token argument	Arguments named access_token, auth_token, api_token, or authorization can be used for the Authorization header.
Template token	API token values such as Bearer %(access_token)s are filled from function arguments.
Template headers	Custom headers can also use %(key)s substitutions from function arguments.

Bare token values are normalized to Bearer <token> when they come from token argument fields. If the argument is named authorization, DialNexa sends the value as provided.

Example JSON Schema Pattern

{
  "type": "object",
  "properties": {
    "customer_id": { "type": "string" },
    "requested_slot": { "type": "string" }
  },
  "required": ["customer_id"]
}

Speech Behavior While A Function Runs

Callers should not sit in silence without context.

Holding message

Short message spoken before calling the tool, useful when the API may take time.

Speak during execution

Allows the agent to keep the caller informed while the tool runs.

Speak after execution

Lets the agent explain the result after the tool returns.

Response variables

Expose API result values that the agent can mention or use in the next turn.

Custom Function Review Questions

Can the function fail gracefully?

Write prompt instructions for API errors, missing data, and timeouts.

Is the timeout realistic?

A very long timeout may keep a caller waiting. A very short one may fail healthy APIs.

Are secrets in the right place?

Use the API token or connection fields, not dynamic variables in prompts.

Can the model produce valid arguments?

Keep JSON schema simple and test edge cases.

Related Reading

Functions

See all function types.

External Webhooks

Configure event delivery separately.

Dashboard Integrations

Use managed provider actions when they fit the job.

Testing Agents

Test function calls in real calls.