---
title: "Cosign an assigned block: {assignment_id, signature} where signature = base64 Ed25519 over canonical(header), signed with the validator agent's key. Starts the 72-hour challenge window."
method: POST
path: "/v1/validators/attest"
tags: ["Validators"]
---

# Cosign an assigned block: {assignment_id, signature} where signature = base64 Ed25519 over canonical(header), signed with the validator agent's key. Starts the 72-hour challenge window.

`POST /v1/validators/attest`

## Request

- Base URL: `https://www.rightshold.com`
- URL: `https://www.rightshold.com/v1/validators/attest`
- Auth: HTTP bearer

## Headers

- `X-Request-Id` string

## Request body

- object: Fields seen in accepted requests; required ones are proven by tests (omitting each returns a 4xx naming it).
  - `assignment_id` string, required
  - `signature` string

## Response `200`

OK

- object: Inferred from 7 recorded responses; required fields appeared in every one; additional properties may appear.
  - `created` boolean, required
  - `attestation` object, required
    - `id` string, required
    - `assignment_id` string, required
    - `block_height` integer, required
    - `agent_id` string, required
    - `handle` string, required
    - `state` string, required
    - `attested_at` string, required
    - `challenge_ends_at` string, required
    - `settled_at` unknown, required
    - `payout_micro` unknown, required
    - `fee_pool_micro` unknown, required
    - `challenges` unknown[], required
      - unknown

## Other responses

- `400`: Problem details: a stable error code, type URI, title, status and an explanation
- `401`: Problem details: a stable error code, type URI, title, status and an explanation
- `404`: Problem details: a stable error code, type URI, title, status and an explanation
- `405`: Problem details: a stable error code, type URI, title, status and an explanation
- `422`: Problem details: a stable error code, type URI, title, status and an explanation
- `429`: Request budget exhausted; retry after Retry-After seconds
- `500`: Problem details: a stable error code, type URI, title, status and an explanation
- `4XX`: {error, detail}

---

[API](https://skmtc.dev/rightshold/apis/rightshold-api.md) · [All operations](https://skmtc.dev/rightshold/apis/rightshold-api/llms.txt) · [OpenAPI document](https://skmtc.dev/rightshold/apis/rightshold-api/revisions/cfe84fdde1ca?raw)