curl --request PATCH \
  --url https://api.cartesia.ai/v1/agents/tools/{tool_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Cartesia-Version: <cartesia-version>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "assignments": [
    {
      "dynamic_variable": "customer_name",
      "value_path": "customer.name"
    }
  ]
}
'

import requests

url = "https://api.cartesia.ai/v1/agents/tools/{tool_id}"

payload = { "assignments": [
        {
            "dynamic_variable": "customer_name",
            "value_path": "customer.name"
        }
    ] }
headers = {
    "Cartesia-Version": "<cartesia-version>",
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PATCH',
  headers: {
    'Cartesia-Version': '<cartesia-version>',
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    assignments: [{dynamic_variable: 'customer_name', value_path: 'customer.name'}]
  })
};

fetch('https://api.cartesia.ai/v1/agents/tools/{tool_id}', 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://api.cartesia.ai/v1/agents/tools/{tool_id}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PATCH",
  CURLOPT_POSTFIELDS => json_encode([
    'assignments' => [
        [
                'dynamic_variable' => 'customer_name',
                'value_path' => 'customer.name'
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Cartesia-Version: <cartesia-version>",
    "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://api.cartesia.ai/v1/agents/tools/{tool_id}"

	payload := strings.NewReader("{\n  \"assignments\": [\n    {\n      \"dynamic_variable\": \"customer_name\",\n      \"value_path\": \"customer.name\"\n    }\n  ]\n}")

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

	req.Header.Add("Cartesia-Version", "<cartesia-version>")
	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.patch("https://api.cartesia.ai/v1/agents/tools/{tool_id}")
  .header("Cartesia-Version", "<cartesia-version>")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"assignments\": [\n    {\n      \"dynamic_variable\": \"customer_name\",\n      \"value_path\": \"customer.name\"\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.cartesia.ai/v1/agents/tools/{tool_id}")

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

request = Net::HTTP::Patch.new(url)
request["Cartesia-Version"] = '<cartesia-version>'
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"assignments\": [\n    {\n      \"dynamic_variable\": \"customer_name\",\n      \"value_path\": \"customer.name\"\n    }\n  ]\n}"

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

{
  "type": "webhook",
  "name": "lookup_customer",
  "description": "Look up the caller to find their customer details.",
  "pre_tool_speech": "auto",
  "execution_mode": "immediate",
  "api_schema": {
    "url": "https://api.example.com/customers/lookup",
    "method": "GET",
    "query_params_schema": {
      "properties": {
        "phone_number": {
          "type": "string",
          "dynamic_variable": "system__caller_id"
        }
      }
    }
  },
  "assignments": [
    {
      "dynamic_variable": "customer_name",
      "value_path": "customer.name"
    }
  ],
  "id": "agent_tool_5RkP2wZmQ8xTnLc4vB7dHy",
  "response_timeout_secs": 20,
  "created_at": "2026-09-15T12:00:00Z",
  "updated_at": "2026-09-15T12:00:00Z"
}

{
  "message": "<string>",
  "request_id": "<string>",
  "title": "<string>",
  "doc_url": "<string>",
  "error_code": "<string>"
}