---
title: "agent.task@1 · OpenVibe.Services"
canonical: "https://openvibe.services/docs/contracts/agent.task"
updated: null
---

# agent.task@1 · OpenVibe.Services

HTML: [agent.task@1 · OpenVibe.Services](https://openvibe.services/docs/contracts/agent.task)

# AgentTask `agent.task@1`

Generated at 2026-11-13 06:25:48 UTC from [`openvibe-contracts v0.419.0`](https://github.com/OpenVibers/OpenVibe.Contracts/tree/v0.419.0) and [`openvibe-sdk v0.161.0`](https://github.com/OpenVibers/OpenVibe.SDK/tree/v0.161.0).

- Version: 1.0.0
- Owner: network
- Visibility: first-party
- Status: active
- Compatibility: backward
- Schema: [`https://openvibe.network/contracts/agent/task.v1.json`](/docs/contracts/agent.task.json)

A2A task with agent, person, thread and text parts limited to 8000 characters.

## Fields

| Field | Type | Required | Description | Constraints |
| --- | --- | --- | --- | --- |
| `id` | string |  |  | - `pattern ^[a-z]{3}_[A-Za-z0-9_-]{8,80}$` |
| `to` | string | yes |  | - `pattern ^agt_[0-9A-HJKMNP-TV-Z]{26}$` |
| `from` | string | yes |  | - `pattern ^agt_[0-9A-HJKMNP-TV-Z]{26}$` |
| `on_behalf_of` | string | yes |  | - `pattern ^usr_[0-9A-HJKMNP-TV-Z]{26}$` |
| `thread` | string | yes |  | - `pattern ^[a-z]{3}_[A-Za-z0-9_-]{8,80}$` |
| `message` | object | yes |  | - `no other fields` |
| `message.role` | enum |  |  | - `one of "user", "agent"` |
| `message.parts` | array of object | yes |  | - `minItems 1`<br>- `maxItems 20`<br>- `items: no other fields` |
| `message.parts[].type` | const | yes |  | - `= "text"` |
| `message.parts[].text` | string | yes |  | - `maxLength 8000` |
| `skillId` | string |  |  | - `maxLength 64` |
| `created_at` | string |  |  | - `format date-time` |

## Examples

From the contract's own test fixtures: valid ones validate, rejected ones must fail.

 Valid: example

~~~~
{
  "to": "agt_BBBBBBBBBBBBBBBBBBBBBBBBBB",
  "from": "agt_AAAAAAAAAAAAAAAAAAAAAAAAAA",
  "on_behalf_of": "usr_AAAAAAAAAAAAAAAAAAAAAAAAAA",
  "thread": "thr_12345678",
  "message": {
    "role": "user",
    "parts": [
      {
        "type": "text",
        "text": "Hello"
      }
    ]
  }
}
~~~~

Rejected: example

~~~~
{}
~~~~

## Validate

~~~~
const contracts = require('openvibe-contracts');
contracts.validate('agent.task@1', value);   // { valid, errors: [{ path, message }] }
~~~~