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The Call User tool (call_user) can request an outbound call during a chat conversation. Configure it for customers who explicitly ask to speak by phone, and test the destination before enabling the workflow.

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Before you start

Use an assistant configured for voice with a valid outbound number. Verify that the account can place a normal outbound test call. The customer must supply or confirm a reachable number with a country code. The standard tool uses the assistant identity supplied by the conversation. It should not be treated as an automatic handoff to a different sales or support assistant.

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Set up the request

  1. Open the assistant’s Tool Kit → Tools & APIs.
  2. Find Call User and add it to the assistant.
  3. Tell the assistant to ask for permission to call now and confirm the phone number before invoking the tool. For example:
    If the customer requests a phone call, confirm the number and that they want us to call now. Use Call User once. Report a failed request honestly and do not repeatedly redial without a new request.
  4. Save and publish the assistant.
  5. Start a test chat and request a call to a phone you control.

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Call request fields

The native shared tool asks for phone_number. The call handler also accepts to or phoneNumber as destination aliases. Supply one confirmed destination, including its country code. The standard conversation supplies the assistant identity. A custom request can also pass from for the outgoing number; it still must be valid for the assistant’s calling setup. This is not a separate From control in the native tool assignment screen. Adding reason or context does not establish transcript transfer to the voice call. A successful tool result has ok: true and call with the call request result. A failed result has ok: false and error. Confirm the phone connection separately.

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Verify the handoff

Confirm that the intended phone rings, the expected caller number is used, and the correct voice assistant answers. Continue the conversation, end the call, and find the matching call record. Do not assume the tool transfers the SMS transcript or a model-supplied context value into the voice call. The standard call request does not establish that handoff. Test what the voice assistant actually knows; if your workflow requires additional context or a different assistant, implement and validate a custom calling integration using the current Calls API.

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API attachment

call_user is excluded from the assistant API’s platform_tools list. Discover it in the tools list and use the explicit tool assignment endpoint. See Platform tools for this exception, and the v3 API introduction for current authentication and reference links.

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Troubleshooting

  • No call requested: inspect tool assignment and its result before trying again.
  • Invalid destination: confirm the full number and country code.
  • Request accepted but phone does not ring: inspect the call record and carrier result; acceptance does not prove connection.
  • Assistant lacks chat context: use a tested context-passing integration rather than adding an unsupported parameter to the native tool.
Place an outbound call