Update evaluator

curl --request PATCH \
  --url https://api.arize.com/v2/evaluators/{evaluator_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "Updated Evaluator Name",
  "description": "Updated description"
}
'

import requests

url = "https://api.arize.com/v2/evaluators/{evaluator_id}"

payload = {
    "name": "Updated Evaluator Name",
    "description": "Updated description"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PATCH',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({name: 'Updated Evaluator Name', description: 'Updated description'})
};

fetch('https://api.arize.com/v2/evaluators/{evaluator_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.arize.com/v2/evaluators/{evaluator_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([
    'name' => 'Updated Evaluator Name',
    'description' => 'Updated description'
  ]),
  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://api.arize.com/v2/evaluators/{evaluator_id}"

	payload := strings.NewReader("{\n  \"name\": \"Updated Evaluator Name\",\n  \"description\": \"Updated description\"\n}")

	req, _ := http.NewRequest("PATCH", 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.patch("https://api.arize.com/v2/evaluators/{evaluator_id}")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"name\": \"Updated Evaluator Name\",\n  \"description\": \"Updated description\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.arize.com/v2/evaluators/{evaluator_id}")

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

request = Net::HTTP::Patch.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"name\": \"Updated Evaluator Name\",\n  \"description\": \"Updated description\"\n}"

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

{
  "id": "RXZhbHVhdG9yOjEyOmFCY0Q=",
  "name": "Updated Evaluator Name",
  "description": "Updated description",
  "type": "TEMPLATE",
  "space_id": "U3BhY2U6NDkzOkJaSkc=",
  "created_at": "2026-02-16T22:05:47.900Z",
  "updated_at": "2026-02-17T10:30:00.000Z",
  "created_by_user_id": "VXNlcjoxOm5OYkM="
}

{
  "status": 400,
  "title": "Invalid request parameters",
  "detail": "The 'name' field is required and must be a non-empty string.",
  "instance": "/resource",
  "type": "https://arize.com/docs/ax/rest-reference/errors#invalid-request"
}

{
  "status": 401,
  "title": "Authentication required",
  "detail": "You must be authenticated to access this resource.",
  "instance": "/resource",
  "type": "https://arize.com/docs/ax/rest-reference/errors#authentication-required"
}

{
  "status": 403,
  "title": "Access forbidden",
  "detail": "You do not have permission to access this resource.",
  "instance": "/resource/12345",
  "type": "https://arize.com/docs/ax/rest-reference/errors#access-forbidden"
}

{
  "status": 404,
  "title": "Resource not found",
  "detail": "The requested resource with ID '12345' was not found.",
  "instance": "/resource/12345",
  "type": "https://arize.com/docs/ax/rest-reference/errors#resource-not-found"
}

{
  "status": 409,
  "title": "Resource conflict",
  "detail": "A resource with the given identifier already exists.",
  "instance": "/resource",
  "type": "https://arize.com/docs/ax/rest-reference/errors#resource-conflict"
}

{
  "status": 422,
  "title": "Unprocessable Entity",
  "detail": "One or more fields failed validation.",
  "instance": "/resource/12345",
  "type": "https://arize.com/docs/ax/rest-reference/errors#unprocessable-entity"
}

{
  "status": 429,
  "title": "Rate limit exceeded",
  "detail": "You have exceeded the allowed number of requests. Please try again later.",
  "instance": "/resource",
  "type": "https://arize.com/docs/ax/rest-reference/errors#rate-limit-exceeded"
}

Evaluators

Update evaluator

Update an evaluator’s metadata. At least one field must be provided. Omitted fields are left unchanged.

Payload Requirements

At least one of name or description must be provided.
name, if provided, must be unique within the space.
System-managed fields (id, type, space_id, created_at, updated_at, created_by_user_id) cannot be modified.

Valid example

{
  "name": "Hallucination Detector v2",
  "description": "Updated evaluator for production hallucination checks"
}

Invalid example (no updatable fields provided)

{}

This endpoint is in beta, read more here.

PATCH

evaluators

{evaluator_id}

Update evaluator

curl --request PATCH \
  --url https://api.arize.com/v2/evaluators/{evaluator_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "Updated Evaluator Name",
  "description": "Updated description"
}
'

import requests

url = "https://api.arize.com/v2/evaluators/{evaluator_id}"

payload = {
    "name": "Updated Evaluator Name",
    "description": "Updated description"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PATCH',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({name: 'Updated Evaluator Name', description: 'Updated description'})
};

fetch('https://api.arize.com/v2/evaluators/{evaluator_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.arize.com/v2/evaluators/{evaluator_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([
    'name' => 'Updated Evaluator Name',
    'description' => 'Updated description'
  ]),
  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://api.arize.com/v2/evaluators/{evaluator_id}"

	payload := strings.NewReader("{\n  \"name\": \"Updated Evaluator Name\",\n  \"description\": \"Updated description\"\n}")

	req, _ := http.NewRequest("PATCH", 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.patch("https://api.arize.com/v2/evaluators/{evaluator_id}")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"name\": \"Updated Evaluator Name\",\n  \"description\": \"Updated description\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.arize.com/v2/evaluators/{evaluator_id}")

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

request = Net::HTTP::Patch.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"name\": \"Updated Evaluator Name\",\n  \"description\": \"Updated description\"\n}"

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

{
  "id": "RXZhbHVhdG9yOjEyOmFCY0Q=",
  "name": "Updated Evaluator Name",
  "description": "Updated description",
  "type": "TEMPLATE",
  "space_id": "U3BhY2U6NDkzOkJaSkc=",
  "created_at": "2026-02-16T22:05:47.900Z",
  "updated_at": "2026-02-17T10:30:00.000Z",
  "created_by_user_id": "VXNlcjoxOm5OYkM="
}

{
  "status": 400,
  "title": "Invalid request parameters",
  "detail": "The 'name' field is required and must be a non-empty string.",
  "instance": "/resource",
  "type": "https://arize.com/docs/ax/rest-reference/errors#invalid-request"
}

{
  "status": 401,
  "title": "Authentication required",
  "detail": "You must be authenticated to access this resource.",
  "instance": "/resource",
  "type": "https://arize.com/docs/ax/rest-reference/errors#authentication-required"
}

{
  "status": 403,
  "title": "Access forbidden",
  "detail": "You do not have permission to access this resource.",
  "instance": "/resource/12345",
  "type": "https://arize.com/docs/ax/rest-reference/errors#access-forbidden"
}

{
  "status": 404,
  "title": "Resource not found",
  "detail": "The requested resource with ID '12345' was not found.",
  "instance": "/resource/12345",
  "type": "https://arize.com/docs/ax/rest-reference/errors#resource-not-found"
}

{
  "status": 409,
  "title": "Resource conflict",
  "detail": "A resource with the given identifier already exists.",
  "instance": "/resource",
  "type": "https://arize.com/docs/ax/rest-reference/errors#resource-conflict"
}

{
  "status": 422,
  "title": "Unprocessable Entity",
  "detail": "One or more fields failed validation.",
  "instance": "/resource/12345",
  "type": "https://arize.com/docs/ax/rest-reference/errors#unprocessable-entity"
}

{
  "status": 429,
  "title": "Rate limit exceeded",
  "detail": "You have exceeded the allowed number of requests. Please try again later.",
  "instance": "/resource",
  "type": "https://arize.com/docs/ax/rest-reference/errors#rate-limit-exceeded"
}

Authorizations

Authorization

string

header

required

Most Arize AI endpoints require authentication. For those endpoints that require authentication, include your API key in the request header using the format

Path Parameters

evaluator_id

string

required

The unique evaluator identifier (base64) A universally unique identifier (base64-encoded opaque string).

Example:

"RW50aXR5OjEyMzQ1"

Body

application/json

Body containing evaluator update parameters

name

string

New evaluator name

description

string | null

New description

Response

An evaluator object

An evaluator defines reusable evaluation logic that can be attached to evaluation tasks. The type field determines the kind of evaluation: TEMPLATE (LLM-based template evaluation), CODE (custom code evaluation), or REMOTE (externally hosted evaluation).

string

required

The unique identifier for the evaluator

name

string

required

The name of the evaluator

type

enum<string>

required

The evaluator type:

TEMPLATE — LLM-based evaluator.
CODE — managed built-in evaluators or custom Python code (both are subtypes of CODE, discriminated by the nested CodeConfig.type = MANAGED | CUSTOM).
HARNESS — test harness evaluator.
REMOTE — remote evaluator.

Applies to both the parent Evaluator.type field and every version's type discriminator — a version's type must always match its parent evaluator's type.

Available options:

TEMPLATE,

CODE,

HARNESS,

REMOTE

space_id

string

required

The unique identifier for the space the evaluator belongs to

created_at

string<date-time>

required

When the evaluator was created

updated_at

string<date-time>

required

When the evaluator was last updated

created_by_user_id

string | null

required

The unique identifier for the user who created the evaluator

description

string | null

The description of the evaluator

Skills

API reference

API clients

Update evaluator

Authorizations

Path Parameters

Body

Response