# NFT Ownership Checker

> Verify whether an address holds a token in a given NFT collection.

- canonical: <https://ai.tatum.io/workflows/nft-ownership-checker>

## MCP tools

- `check_owner`
- `get_owners`
- `get_metadata`

## API endpoints

- `GET /v4/data/nft/owners`
- `GET /v4/data/nft/metadata`

## Steps

1. Resolve `contract`, `tokenId`, `chain`, and `address`.
2. Call `check_owner` for the boolean answer.
3. If positive and metadata is requested, call `get_metadata`.

## Possible failures

- Wrong chain for the contract
- Contract not an ERC-721/1155
- Address normalization mismatch

## Recovery guidance

- Validate contract on the requested chain first
- Fall back to `get_owners` if `check_owner` returns ambiguous results
- Always compare addresses checksummed/normalized