Deterministic UTXO consolidation under volatile fee regimes

In the realm of cryptocurrency transactions, particularly when dealing with mempool management and transaction selection, it is critical to distinguish between transaction validity and policy reproducibility. The variability in valid transaction selections from different mempool snapshots does not inherently indicate a failure in system correctness. However, several key properties must be maintained consistently to ensure transaction integrity and economic rationality. These include avoiding the creation of uneconomical change, capping the fees paid in transactions, preserving the status of explicitly frozen or excluded Unspent Transaction Outputs (UTXOs), and necessitating explicit approval before any action that links privacy-sensitive clusters.

To achieve reproducibility of a Partially Signed Bitcoin Transaction (PSBT), detailed records of several parameters are essential. These include the fee estimates at the time of the transaction, the set of eligible UTXOs, the version of the selection policy, and the thresholds set for creating change. Without these details, defining what constitutes the "same wallet state" remains too vague and leads to challenges in replicating transaction conditions accurately at a later stage.

Moreover, the irreversible nature of privacy implications—unlike mere fee regrets—necessitates more cautious handling of transactions that consolidate UTXOs. Such consolidations can inadvertently link previously unrelated clusters of transactions, thereby impacting user privacy significantly. Given these risks, it would be prudent to make consolidation actions either opt-in or subject to separate confirmations to safeguard users' interests and maintain trust in the transaction process.