> ## Documentation Index
> Fetch the complete documentation index at: https://docs.dacard.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Link a signal card

> Attach a generated signal card to a stored score, claim it for the caller's account.

Attach a generated signal card to a stored score, or claim an anonymous signal card for the caller's account after sign-up. Symmetric with `/api/score/link` but for the IC-tier signal card flow.

```bash theme={null}
curl -X POST https://app.dacard.ai/api/signal-card/sigc_xyz/link \
  -H "Authorization: Bearer $DACARD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "scoreId": "scr_xyz" }'
```

| Property | Value |
| - | - |
| **Auth** | Required |
| **Idempotent** | Yes (second call is a no-op) |

## Body

| Field | Type | Required | Notes |
| - | - | - | - |
| `scoreId` | string | no | Pass when linking the signal card to an existing stored score. Otherwise the card is just claimed against the user's account. |

## Errors

| Status | Code | When |
| - | - | - |
| 401 | `AUTH_REQUIRED` | No session. |
| 404 | `Signal card not found` | Bad `id`. |
| 409 | `Already linked to another account` | Card was already claimed. |
| 500 | `INTERNAL_ERROR` | Write failed. |


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