Call with Prompt

curl --request POST \
  --url https://www.callcow.ai/api/call-prompt \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "Book a reservation at Friday 7pm for Josh for 2",
  "recipient_phone": "+14155552671",
  "callback_url": "https://agent.example.com/results",
  "callback_secret": "my-secret-token",
  "idempotency_key": "agent-task-12345"
}
'

import requests

url = "https://www.callcow.ai/api/call-prompt"

payload = {
    "prompt": "Book a reservation at Friday 7pm for Josh for 2",
    "recipient_phone": "+14155552671",
    "callback_url": "https://agent.example.com/results",
    "callback_secret": "my-secret-token",
    "idempotency_key": "agent-task-12345"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    prompt: 'Book a reservation at Friday 7pm for Josh for 2',
    recipient_phone: '+14155552671',
    callback_url: 'https://agent.example.com/results',
    callback_secret: 'my-secret-token',
    idempotency_key: 'agent-task-12345'
  })
};

fetch('https://www.callcow.ai/api/call-prompt', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://www.callcow.ai/api/call-prompt",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'prompt' => 'Book a reservation at Friday 7pm for Josh for 2',
    'recipient_phone' => '+14155552671',
    'callback_url' => 'https://agent.example.com/results',
    'callback_secret' => 'my-secret-token',
    'idempotency_key' => 'agent-task-12345'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://www.callcow.ai/api/call-prompt"

	payload := strings.NewReader("{\n  \"prompt\": \"Book a reservation at Friday 7pm for Josh for 2\",\n  \"recipient_phone\": \"+14155552671\",\n  \"callback_url\": \"https://agent.example.com/results\",\n  \"callback_secret\": \"my-secret-token\",\n  \"idempotency_key\": \"agent-task-12345\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://www.callcow.ai/api/call-prompt")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"prompt\": \"Book a reservation at Friday 7pm for Josh for 2\",\n  \"recipient_phone\": \"+14155552671\",\n  \"callback_url\": \"https://agent.example.com/results\",\n  \"callback_secret\": \"my-secret-token\",\n  \"idempotency_key\": \"agent-task-12345\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://www.callcow.ai/api/call-prompt")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"prompt\": \"Book a reservation at Friday 7pm for Josh for 2\",\n  \"recipient_phone\": \"+14155552671\",\n  \"callback_url\": \"https://agent.example.com/results\",\n  \"callback_secret\": \"my-secret-token\",\n  \"idempotency_key\": \"agent-task-12345\"\n}"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "workflow_id": "b8f40b44-3b7a-425b-a2ae-1327471b0410",
  "call_id": "c9e50c55-4c8b-536c-b3bf-2438582c1521"
}

{
  "error": "Validation failed",
  "details": {}
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

POST

call-prompt

Call with Prompt

curl --request POST \
  --url https://www.callcow.ai/api/call-prompt \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "Book a reservation at Friday 7pm for Josh for 2",
  "recipient_phone": "+14155552671",
  "callback_url": "https://agent.example.com/results",
  "callback_secret": "my-secret-token",
  "idempotency_key": "agent-task-12345"
}
'

import requests

url = "https://www.callcow.ai/api/call-prompt"

payload = {
    "prompt": "Book a reservation at Friday 7pm for Josh for 2",
    "recipient_phone": "+14155552671",
    "callback_url": "https://agent.example.com/results",
    "callback_secret": "my-secret-token",
    "idempotency_key": "agent-task-12345"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    prompt: 'Book a reservation at Friday 7pm for Josh for 2',
    recipient_phone: '+14155552671',
    callback_url: 'https://agent.example.com/results',
    callback_secret: 'my-secret-token',
    idempotency_key: 'agent-task-12345'
  })
};

fetch('https://www.callcow.ai/api/call-prompt', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://www.callcow.ai/api/call-prompt",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'prompt' => 'Book a reservation at Friday 7pm for Josh for 2',
    'recipient_phone' => '+14155552671',
    'callback_url' => 'https://agent.example.com/results',
    'callback_secret' => 'my-secret-token',
    'idempotency_key' => 'agent-task-12345'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://www.callcow.ai/api/call-prompt"

	payload := strings.NewReader("{\n  \"prompt\": \"Book a reservation at Friday 7pm for Josh for 2\",\n  \"recipient_phone\": \"+14155552671\",\n  \"callback_url\": \"https://agent.example.com/results\",\n  \"callback_secret\": \"my-secret-token\",\n  \"idempotency_key\": \"agent-task-12345\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://www.callcow.ai/api/call-prompt")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"prompt\": \"Book a reservation at Friday 7pm for Josh for 2\",\n  \"recipient_phone\": \"+14155552671\",\n  \"callback_url\": \"https://agent.example.com/results\",\n  \"callback_secret\": \"my-secret-token\",\n  \"idempotency_key\": \"agent-task-12345\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://www.callcow.ai/api/call-prompt")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"prompt\": \"Book a reservation at Friday 7pm for Josh for 2\",\n  \"recipient_phone\": \"+14155552671\",\n  \"callback_url\": \"https://agent.example.com/results\",\n  \"callback_secret\": \"my-secret-token\",\n  \"idempotency_key\": \"agent-task-12345\"\n}"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "workflow_id": "b8f40b44-3b7a-425b-a2ae-1327471b0410",
  "call_id": "c9e50c55-4c8b-536c-b3bf-2438582c1521"
}

{
  "error": "Validation failed",
  "details": {}
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

{
  "error": "<string>"
}

Overview

Create and trigger an AI phone call from a natural language prompt in a single request. The system generates a workflow from your prompt, initiates the call, and optionally delivers results to a callback URL. This is ideal for agent-to-agent orchestration, where external agents can make calls without pre-creating workflows.

Callback

If you provide a callback_url, the API will POST call results to that URL when the call completes or fails (including not picked up, busy, voicemail). Callback delivery is best-effort (single attempt, 30-second timeout). For guaranteed delivery, poll the call status as a fallback.

Callback payload

{
  "call_id": "abc-123",
  "workflow_id": "def-456",
  "call_status": "success",
  "provider_status": "completed",
  "call_summary": "Customer booked a reservation for Friday 7pm, party of 2.",
  "messages": [],
  "context": null,
  "form_fills": [],
  "created_at": "2026-03-30T12:00:00.000Z"
}

If you provided a callback_secret, the callback request includes an Authorization: Bearer <your_secret> header.

Terminal statuses

`call_status`	`provider_status`	Meaning
`success`	`completed`	Call completed normally
`not_picked_up`	`no-answer`	No one answered
`not_picked_up`	`busy`	Line was busy
`not_picked_up`	`failed`	Call failed (bad number, carrier error)
`not_picked_up`	`canceled`	Call was canceled
`voicemail`	`completed`	Went to voicemail

Idempotency

To prevent duplicate calls from retries, pass an optional idempotency_key. If the same key is sent within a 5-minute window, the API returns the cached response without creating a new call.

{
  "prompt": "Book a reservation at Friday 7pm for Josh for 2",
  "recipient_phone": "+14155552671",
  "idempotency_key": "agent-task-12345"
}

Authorizations

Authorization

string

header

required

API key generated from Settings → API Keys. Format: ck_live_...

Body

application/json

prompt

string

required

Natural language description of the call task. The system generates an AI workflow from this prompt.

Example:

"Book a reservation at Friday 7pm for Josh for 2"

recipient_phone

string

required

Phone number of the call recipient in E.164 format

Example:

"+14155552671"

callback_url

string<uri>

HTTPS URL to receive call results when the call completes or fails. Must not point to private/reserved IP ranges.

Example:

"https://agent.example.com/results"

callback_secret

string

Optional bearer token included in the Authorization header of callback requests

Example:

"my-secret-token"

idempotency_key

string

Optional unique key to prevent duplicate calls on retries. Scoped to your organization with a 5-minute TTL.

Example:

"agent-task-12345"

Response

Call successfully created and triggered

success

boolean

Example:

true

workflow_id

string

ID of the generated workflow

Example:

"b8f40b44-3b7a-425b-a2ae-1327471b0410"

call_id

string | null

ID of the initiated call, if available

Example:

"c9e50c55-4c8b-536c-b3bf-2438582c1521"

API documentation

Endpoints

Webhooks

Call with Prompt

Overview

Callback

Callback payload

Terminal statuses

Idempotency

Authorizations

Body

Response

​Overview

​Callback

​Callback payload

​Terminal statuses

​Idempotency

Authorizations

Body

Response

Overview

Callback

Callback payload

Terminal statuses

Idempotency