{
  "context": "This criteria evaluates proficiency in using bitcoinjs-lib for Taproot key-path spending, including creating P2TR payment objects, generating Schnorr signatures, and building complete Taproot transactions. The focus is exclusively on correct usage of bitcoinjs-lib's Taproot-specific APIs.",
  "type": "weighted_checklist",
  "checklist": [
    {
      "name": "P2TR payment creation",
      "description": "Uses bitcoinjs-lib's payments.p2tr() function to create a Taproot payment object from an x-only internal public key, correctly handling the network parameter.",
      "max_score": 15
    },
    {
      "name": "Bech32m address encoding",
      "description": "The P2TR payment object correctly generates a Bech32m-encoded Taproot address using the address property from payments.p2tr().",
      "max_score": 10
    },
    {
      "name": "Witness program extraction",
      "description": "Correctly extracts and uses the witness program (output script) from the P2TR payment object for transaction outputs.",
      "max_score": 10
    },
    {
      "name": "Transaction construction",
      "description": "Uses bitcoinjs-lib's Transaction class to properly construct a transaction with addInput() and addOutput() methods, setting appropriate transaction fields.",
      "max_score": 15
    },
    {
      "name": "Taproot sighash computation",
      "description": "Uses Transaction.hashForWitnessV1() method to compute the signature hash for Taproot inputs, passing the correct input index, prevOutScripts, values array, and hash type.",
      "max_score": 20
    },
    {
      "name": "Schnorr signature generation",
      "description": "Generates a valid Schnorr signature using the computed sighash, utilizing an ECC library's signSchnorr() method with the private key.",
      "max_score": 15
    },
    {
      "name": "Witness data structure",
      "description": "Correctly sets the witness field on the transaction input using setWitness() or direct witness array assignment, with the Schnorr signature as the only witness element.",
      "max_score": 10
    },
    {
      "name": "Input value handling",
      "description": "Properly tracks and uses previous output values (in satoshis) when computing Taproot signature hashes, as required for witness v1 signing.",
      "max_score": 5
    }
  ]
}