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call.tool_called

POST

Live: an assistant’s tool call finished during a call (name, arguments, result or error). Opt-in: sent only to endpoints that name this type; * and call.* don’t include it.

Authorizations

Section titled “Authorizations”

Parameters

Section titled “Parameters”

Header Parameters

Section titled “Header Parameters”
webhook-id
required
string

The event ID (evt_…); the same on every retry. Deduplicate on it.

Example
evt_3fT9kq2ZpLr8YwVbN1cX0a
webhook-timestamp
required
string

Unix seconds of this delivery attempt. Reject deliveries more than 5 minutes old.

Example
1762161262
webhook-signature
required
string

Space-separated v1,<base64 HMAC-SHA256> signatures of <webhook-id>.<webhook-timestamp>.<body> with the endpoint secret (two while a secret rotates).

Example
v1,K5oZfzN95Z9UVu1EsfQmfVNQhnkZ2pj9o9NDN/H/pI4=

Request Bodyrequired

Section titled “Request Bodyrequired”
Media typeapplication/json

Live: an assistant’s tool call finished during a call (name, arguments, result or error). Opt-in: sent only to endpoints that name this type; * and call.* don’t include it.

object
api_version
required

The API version the payload is rendered in (the endpoint’s pinned version).

string
created
required

An ISO-8601 timestamp in UTC.

string format: date-time
data
required

object is the object the call.tool_called event is about.

object
object
required
object
arguments
call_id
string
>= 1 characters /^call_[0-9A-Za-z]+$/
error
string | null
name
string
result
status
string
Allowed values: done error
tool_call_id
string
>= 1 characters /^tc_[0-9A-Za-z]+$/
key
additional properties
previous_attributes

For *.updated-style events: the changed attributes’ previous values.

object
key
additional properties
id
required

The event ID. Receivers deduplicate on it (it is also the webhook-id header).

string
/^evt_[0-9A-Za-z]+$/
livemode
required

true in live mode, false in test mode.

boolean
object
required
string
Allowed value: event
org_id
required

The organisation the event belongs to.

string
/^org_[0-9A-Za-z]+$/
request
object
id
required
Any of:

The API request that caused the event (its X-Request-Id), if any.

string
/^req_[0-9A-Za-z]+$/
idempotency_key
required

That request’s Idempotency-Key, if any.

string | null
type
required
string
Allowed value: call.tool_called
Example
{
  "api_version": "2026-11-01",
  "created": "2026-11-03T09:14:22.000Z",
  "data": {
    "object": {
      "arguments": null,
      "call_id": "call_Oxtl48GXWtJCwMfHzxm0oL",
      "error": "…",
      "name": "…",
      "result": null,
      "status": "done",
      "tool_call_id": "tc_UQRmdLaptZPgzVzG5pa87G"
    }
  },
  "id": "evt_3fT9kq2ZpLr8YwVbN1cX0a",
  "livemode": true,
  "object": "event",
  "org_id": "org_0000000000000000000001",
  "request": {
    "id": null,
    "idempotency_key": null
  },
  "type": "call.tool_called"
}

Responses

Section titled “Responses”

2XX

Section titled “2XX”

Acknowledge the event with any 2xx status within 15 seconds. Anything else, or a timeout, is retried for up to 72 hours.