# Withdraw a shared model reference

```http
DELETE /api/public/v1/contributor-network/items/{itemId}
```

**Scope**: `contributor-network.write`.

Withdraws an active Modular Arithmetic Contributor Network model reference authored by the calling account.

The publication becomes unavailable through lists and direct item reads, while its immutable record and lineage edges are retained. The external Hugging Face repository and formal competition resources are unchanged.

## Path parameters

| Parameter | Type | Required | Description |
| :--- | :--- | :---: | :--- |
| `itemId` | string | Yes | Stable ID of the Modular Arithmetic publication to withdraw. |

## Query parameters

| Parameter | Type | Required | Description |
| :--- | :--- | :---: | :--- |
| `competitionId` | string | Yes | Must be `modular-arithmetic-challenge`. |
| `kind` | string | Yes | Must be `model-reference`. |

The discriminators prevent a Modular Arithmetic client from withdrawing an item from another competition or Contributor Network kind. Withdrawal rechecks item identity and author ownership, but does not require the competition to remain active or the author to remain enrolled, belong to a team, own that team, or be inside the formal-submission window. A later change to the external model's availability also does not block withdrawal.

## Example request

```bash
curl -X DELETE \
  --url "https://api.sair.foundation/api/public/v1/contributor-network/items/$ITEM_ID" \
  --url-query "competitionId=modular-arithmetic-challenge" \
  --url-query "kind=model-reference" \
  -H "Authorization: Bearer $SAIR_API_KEY"
```

## Response

Returns `204 No Content` with no response body.

The operation is naturally idempotent and does not use an `idempotencyKey`. Repeating it as the original author after a successful withdrawal returns `204` again and does not release active capacity more than once.

Withdrawal does not delete or modify:

- the referenced Hugging Face repository or revision;
- the team's formal submission slots, official evaluation records, or existing Playground Run snapshots;
- active descendants of this publication;
- lineage references, which expose the withdrawn item only as `available: false`.

Withdrawing releases one active-publication-capacity slot but does not restore the UTC-day creation quota. Publishing the same model revision later is a new operation with a new `idempotencyKey`, item ID, public code, and publication time; the withdrawn item is never reactivated, and its favorites or comments are not transferred.

## Errors

| HTTP | Code | When |
| :---: | :--- | :--- |
| `403` | `ITEM_NOT_AUTHOR` | The matching active item exists, but the calling account is not its author. |
| `404` | `NOT_FOUND` | The item is missing, does not match the required competition and kind, or is inactive for a reason other than this caller's completed withdrawal. |
| `422` | `RESOURCE_FIELD_INVALID` | A required discriminator is missing or invalid. |

See [Errors](../../../errors.md) for shared authentication, scope, and rate-limit errors.