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Asset Types

Every FlowGuard covenant supports two asset modes selected by FLAG_USES_TOKENS (0x04 in the flags byte):
ModeFlagWhat is heldOutput enforcement
BCH modeFLAG_USES_TOKENS = 0Satoshis in the UTXO valuetx.outputs[0].value == amount
Token modeFLAG_USES_TOKENS = 1CashToken FT unitstx.outputs[0].tokenAmount == amount
The mode is set at deployment and encoded into the NFT flags byte. It cannot change.

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BCH Streams

In BCH mode, the covenant holds satoshis directly. Amounts are expressed in satoshis (1 BCH = 100,000,000 satoshis). The minimum meaningful amount is limited by the BCH dust limit (~546 satoshis).

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CashToken Streams

In token mode, the covenant holds CashToken fungible token units. The tokenCategory of the NFT and the FT escrow are the same, linking them in a single UTXO. The token amount field tracks the escrowed FT units separately from the BCH satoshi value (which only covers the UTXO dust amount).
When creating a CashToken stream, the covenant UTXO must hold both:
  1. A small BCH dust amount to make the UTXO valid
  2. The FT amount to be streamed under the same tokenCategory as the state NFT

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Supported Token Standards

Any CashToken fungible token with a valid tokenCategory is supported. This includes:
  • BCMR-registered tokens with published metadata
  • Protocol tokens (DeFi, governance, utility)
  • Unregistered fungible tokens with any category
FlowGuard does not whitelist or verify token categories at the contract level. Sender and recipient are responsible for verifying the token being streamed.