Example tags used in Tapscript:

def tagged_hash(tag: str, data: bytes) -> bytes:
    tag_hash = sha256(tag.encode())
    return sha256(tag_hash + tag_hash + data)

# Example tags used in Tapscript:
# "TapSighash"
# "TapLeaf"
# "TapBranch"
# "TapTweak"

def tapscript_sighash(tx, input_index, utxos, hash_type, annex=None, tap_leaf=None):
    """
    Compute the Tapscript signature hash per BIP 341.

    tx:           the spending transaction
    input_index:  which input we are signing
    utxos:        list of all UTXOs being spent (needed for all inputs)
    hash_type:    SIGHASH flag byte
    annex:        optional annex data (BIP 341)
    tap_leaf:     tapscript leaf hash (for script path spending)
    """

    # Epoch (always 0x00 for current Tapscript)
    epoch = bytes([0x00])

    # Hash type
    hash_type_byte = bytes([hash_type])

    # Transaction data
    n_version = tx.nVersion.to_bytes(4, 'little')
    n_locktime = tx.nLockTime.to_bytes(4, 'little')

    # Commit to all inputs
    sha_prevouts = sha256(b''.join(
        inp.prevout.serialize() for inp in tx.vin
    ))

    # Commit to all input amounts (NEW vs legacy)
    sha_amounts = sha256(b''.join(
        utxo.nValue.to_bytes(8, 'little') for utxo in utxos
    ))

    # Commit to all input scriptPubKeys (NEW vs legacy)
    sha_scriptpubkeys = sha256(b''.join(
        ser_string(utxo.scriptPubKey) for utxo in utxos
    ))

    # Commit to all sequences
    sha_sequences = sha256(b''.join(
        inp.nSequence.to_bytes(4, 'little') for inp in tx.vin
    ))

    # Commit to all outputs
    sha_outputs = sha256(b''.join(
        out.serialize() for out in tx.vout
    ))

    # Spend type: key path vs script path, annex presence
    spend_type = 0x00
    if annex: spend_type |= 0x01
    if tap_leaf: spend_type |= 0x02
    spend_type_byte = bytes([spend_type])

    # Input-specific data
    this_input = tx.vin[input_index]
    input_data = (
        utxos[input_index].nValue.to_bytes(8, 'little') +
        ser_string(utxos[input_index].scriptPubKey) +
        this_input.nSequence.to_bytes(4, 'little')
    )

    # Optional: annex hash
    annex_data = b''
    if annex:
        annex_data = sha256(ser_string(annex))

    # Optional: tap leaf hash (for script path)
    tap_leaf_data = b''
    if tap_leaf:
        tap_leaf_data = tap_leaf  # 32-byte hash

    # Assemble preimage
    preimage = (
        epoch + hash_type_byte + n_version + n_locktime +
        sha_prevouts + sha_amounts + sha_scriptpubkeys +
        sha_sequences + sha_outputs + spend_type_byte +
        input_data + annex_data + tap_leaf_data
    )

    return tagged_hash("TapSighash", preimage)

SIGHASH_DEFAULT    = 0x00  (new in Tapscript — same as ALL but 1 byte shorter signature)
SIGHASH_ALL        = 0x01
SIGHASH_NONE       = 0x02
SIGHASH_SINGLE     = 0x03
SIGHASH_ANYONECANPAY = 0x80  (can be OR'd with above)