---
title: "Correct, Supersede, or Retract a Claim"
description: "Append a correction or retraction while preserving earlier evidence."
canonical: https://y2.dev/docs/ontology/how-to/correct-a-claim/
---

Ontology & Fusion

# Correct, Supersede, or Retract a Claim

Append a correction or retraction while preserving earlier evidence.

Each correction replaces the current head of a claim key: `predicate|from|to|qualifier`. Earlier records remain in the ledger.

API requests require a workspace-bound key with `ledger:read` and `ledger:write`. Set `Y2_SUBJECT_ID` to the subject's actual ID. Replace the IDs in the JSON templates below with IDs from your ledger.

## Find the current head

The app shows the live claim for each designation and relationship. For API access, read the subject:

```
curl --fail --silent --show-error \
  "https://api.y2.dev/api/v2/ledger/subjects/$Y2_SUBJECT_ID" \
  --header "Authorization: Bearer $Y2_API_KEY"
```

Retain the current `claimId` for the claim you will replace.

## Strengthen a claim with a second source

In the app, record the same identifier with the second source. Select `cross-linked` only when the evidence supports it. Y2 retains the earlier evidence and supersedes the previous claim.

Through the API, append the second observation first. Then submit a claim with both evidence IDs and the current head:

```
{
  "kind": "claim",
  "claim": {
    "predicate": "designated-by",
    "from": "SUBJECT_ID",
    "to": "DESIGNATOR_ID",
    "supersedes": "CURRENT_CLAIM_ID",
    "confidence": 90,
    "verification": "cross-linked",
    "evidenceRefs": ["FIRST_OBSERVATION_ID", "SECOND_OBSERVATION_ID"]
  }
}
```

Choose a confidence value supported by your evidence. The value shown here illustrates the field. Submit the payload with [Append a record](https://y2.dev/docs/api/reference/ontology-ledger/appendLedgerRecordV2).

## Close an interval when a page changes

If a later retrieval no longer shows the identifier, supersede the claim with `validTo`. Cite both retrievals. Retain the claim's confidence and verification state.

Use source-supported dates. If only retrievals establish the dates, describe the interval as a sighting interval in `note`. The end is exclusive. Omit an unknown bound instead of guessing it.

## Retract a mistaken claim

First record an observation that explains the error, usually an analyst note. Then append a retraction:

```
{
  "kind": "claim",
  "claim": {
    "op": "retract",
    "predicate": "designated-by",
    "from": "SUBJECT_ID",
    "to": "DESIGNATOR_ID",
    "supersedes": "CURRENT_CLAIM_ID",
    "evidenceRefs": ["EXPLANATION_OBSERVATION_ID"],
    "note": "The earlier attachment relied only on a shared name."
  }
}
```

Omit confidence, verification, and interval fields on a retraction. The retracted claim leaves the current view but remains in history. A later assertion must supersede the retraction.

## If the request is rejected

| Response                        | Cause                               | Action                                          |
| ------------------------------- | ----------------------------------- | ----------------------------------------------- |
| `409`, `assertion.chain`        | Missing or outdated `supersedes`    | Read the subject again and use the current head |
| `400`, `assertion.verification` | Evidence does not support the state | Add suitable evidence or reduce the state       |

See [record rules](https://y2.dev/docs/ontology/reference/ledger-format#rules) for other errors.