curl --request PATCH \
  --url https://api.arize.com/v2/tasks/{task_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data @- <<EOF
{
  "name": "Updated Task Name",
  "sampling_rate": 0.5,
  "query_filter": "metadata.environment = 'staging'"
}
EOF

{
  "id": "T25saW5lVGFzazo0NTpxUndY",
  "name": "Production Hallucination Check",
  "type": "TEMPLATE_EVALUATION",
  "project_id": "TW9kZWw6MTIzOmFCY0Q=",
  "dataset_id": null,
  "sampling_rate": 1,
  "is_continuous": true,
  "query_filter": null,
  "evaluators": [
    {
      "evaluator_id": "RXZhbHVhdG9yOjEyOmFCY0Q=",
      "evaluator_name": "Hallucination Eval",
      "query_filter": null,
      "column_mappings": {
        "input": "attributes.input.value",
        "output": "attributes.output.value"
      }
    }
  ],
  "experiment_ids": [],
  "last_run_at": "2026-03-01T14:30:00.000Z",
  "created_at": "2026-02-20T10:00:00.000Z",
  "updated_at": "2026-02-20T10:00:00.500Z",
  "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": 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"
}

Tasks

Update task

Update a task’s mutable fields. At least one field must be provided. Omitted fields are left unchanged.

Payload Requirements

At least one mutable field must be provided.
When evaluators is provided, the entire evaluator list is replaced.
sampling_rate and is_continuous are only applicable for project-based tasks.
Fields not valid for the task’s type return 400 (e.g. run_configuration on an evaluation task).
System-managed fields (id, type, created_at, updated_at) cannot be modified.
evaluator_version_id pins an evaluator to one version. Because evaluators replaces the whole list, each entry states its own pin: send a version ID to pin, and omit the field or send null to run the latest version. Omit evaluators entirely to leave the existing attachments — and their pins — untouched.
A pinned version must belong to the evaluator named by evaluator_id, and every evaluator on the task must resolve to the same data scope. Both return 422.

Valid example (update evaluation task)

{
  "name": "Updated Hallucination Check",
  "sampling_rate": 0.5,
  "query_filter": "metadata.environment = 'staging'"
}

Valid example (pin one evaluator, leave the other on latest)

{
  "evaluators": [
    {
      "evaluator_id": "RXZhbHVhdG9yOjEyOmFCY0Q=",
      "evaluator_version_id": "RXZhbHVhdG9yVmVyc2lvbjo5OTphQmNE"
    },
    {
      "evaluator_id": "RXZhbHVhdG9yOjEzOmFCY0Q="
    }
  ]
}

Invalid example (no fields provided)

{}

This endpoint is in beta, read more here.

PATCH

tasks

{task_id}

curl --request PATCH \
  --url https://api.arize.com/v2/tasks/{task_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data @- <<EOF
{
  "name": "Updated Task Name",
  "sampling_rate": 0.5,
  "query_filter": "metadata.environment = 'staging'"
}
EOF

{
  "id": "T25saW5lVGFzazo0NTpxUndY",
  "name": "Production Hallucination Check",
  "type": "TEMPLATE_EVALUATION",
  "project_id": "TW9kZWw6MTIzOmFCY0Q=",
  "dataset_id": null,
  "sampling_rate": 1,
  "is_continuous": true,
  "query_filter": null,
  "evaluators": [
    {
      "evaluator_id": "RXZhbHVhdG9yOjEyOmFCY0Q=",
      "evaluator_name": "Hallucination Eval",
      "query_filter": null,
      "column_mappings": {
        "input": "attributes.input.value",
        "output": "attributes.output.value"
      }
    }
  ],
  "experiment_ids": [],
  "last_run_at": "2026-03-01T14:30:00.000Z",
  "created_at": "2026-02-20T10:00:00.000Z",
  "updated_at": "2026-02-20T10:00:00.500Z",
  "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": 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

task_id

string

required

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

Example:

"RW50aXR5OjEyMzQ1"

Body

application/json

PATCH body for PATCH /v2/tasks/{task_id}. The server derives the task type from the URL's task record and selects the appropriate schema; the body itself does not carry a type field.

Task type	Schema
`TEMPLATE_EVALUATION`	`UpdateEvaluationTaskRequest`
`CODE_EVALUATION`	`UpdateEvaluationTaskRequest`
`RUN_EXPERIMENT`	`UpdateRunExperimentTaskRequest`

For TEMPLATE_EVALUATION and CODE_EVALUATION tasks, at least one of name, sampling_rate, is_continuous, query_filter, or evaluators must be provided.

For RUN_EXPERIMENT tasks, at least one of name or run_configuration must be provided. When run_configuration is provided the stored config is atomically replaced.

Sending a field that is not valid for the resolved task type returns 400 (e.g. evaluators on a RUN_EXPERIMENT task, or run_configuration on an evaluation task).

Option 1
Option 2

PATCH body for PATCH /v2/tasks/{task_id}. The server derives the task type from the URL's task record and selects the appropriate schema; the body itself does not carry a type field.

Task type	Schema
`TEMPLATE_EVALUATION`	`UpdateEvaluationTaskRequest`
`CODE_EVALUATION`	`UpdateEvaluationTaskRequest`
`RUN_EXPERIMENT`	`UpdateRunExperimentTaskRequest`

Sending a field that is not valid for the resolved task type returns 400 (e.g. evaluators on a RUN_EXPERIMENT task, or run_configuration on an evaluation task).

name

string

New task name.

Minimum string length: 1

sampling_rate

number

Sampling rate between 0 and 1. Only applicable for project-based tasks.

Required range: 0 <= x <= 1

is_continuous

boolean

Whether the task runs continuously. Only applicable for project-based tasks.

query_filter

string | null

Task-level query filter (span shape). Pass null to clear. Mutually exclusive with query_filters.

query_filters

object | null

Named query filters plus optional expression (trace/session shape). Pass null to clear the entire multi-query shape (filters and expression together). Mutually exclusive with query_filter.

Show child attributes

evaluators

object[]

Replaces the entire evaluator list. At least one evaluator is required when provided. Omit the field to leave evaluators unchanged.

Minimum array length: 1

An evaluator attachment supplied when creating or updating a task. At least one entry is required on evaluation-task requests. Evaluators carry one of two mutually exclusive shapes: span evaluators use query_filter + column_mappings; trace/session evaluators use query_mappings.

Option 1
Option 2

Show child attributes

Response

Returns a single task object

A task is a typed, configurable unit of work that ties one or more evaluators to a data source (project or dataset). RUN_EXPERIMENT tasks additionally carry a run_configuration that defines the LLM, evaluator, or agent settings for each triggered run.

Evaluation tasks (TEMPLATE_EVALUATION and CODE_EVALUATION) use one of two mutually exclusive query-filter shapes depending on the granularity of the data each evaluator processes:

Span shape — query_filter (task-level) plus per-evaluator column_mappings/query_filter. For tasks where each evaluated unit is a single span. query_filters is null.
Trace/session shape — query_filters (named filters plus optional expression) at the task level, and per-evaluator query_mappings. For tasks where each evaluated unit is a complete trace or session. query_filter is null.

All evaluators on a task must use the same shape; mixing shapes returns 400.

string

required

The unique identifier for the task

name

string

required

The name of the task

type

enum<string>

required

The task type.

TEMPLATE_EVALUATION - An LLM template-based evaluation task.
CODE_EVALUATION - A code-based evaluation task.
RUN_EXPERIMENT - A task that runs experiments.

Available options:

TEMPLATE_EVALUATION,

CODE_EVALUATION,

RUN_EXPERIMENT

is_continuous

boolean

required

Whether the task runs continuously on incoming data.

query_filter

string | null

required

Task-level query filter applied to all data. Span-granularity shape only. Null when the task uses the trace/session shape (query_filters). Mutually exclusive with query_filters.

evaluators

object[]

required

The evaluators attached to this task. Empty for run_experiment tasks.

Show child attributes

experiment_ids

string[]

required

Experiment identifiers (base64) for dataset-based tasks.

last_run_at

string<date-time> | null

required

When the task was last run.

created_at

string<date-time>

required

When the task was created.

updated_at

string<date-time>

required

When the task was last updated.

created_by_user_id

string | null

required

The unique identifier for the user who created the task.

project_id

string | null

The project identifier (base64). Present for project-based tasks.

dataset_id

string | null

The dataset identifier (base64). Present for dataset-based tasks.

sampling_rate

number | null

Sampling rate between 0 and 1. Only applicable for project-based tasks.

Required range: 0 <= x <= 1

query_filters

object | null

Named query filters plus optional boolean expression for trace/session-granularity evaluators. Null for span-granularity tasks (which use query_filter). Mutually exclusive with query_filter.

Show child attributes

run_configuration

object

The run configuration for a RUN_EXPERIMENT task. Present only when type is RUN_EXPERIMENT. Null for all other task types.

Option 1
Option 2
Option 3

Show child attributes

Skills

API reference

API clients

Update task

Authorizations

Path Parameters

Body

Response