Settlement & USDFC

See Concepts → Payment rails for the model. This page is the operator's view: what to expect, what to monitor, when to intervene.

What happens automatically

Every 10 minutes, the singleton task PDPv0_PaySettle runs and:

1. Discovers all rails on FilecoinPay with this SP as payee (USDFC token).
2. Upserts each rail into pdp_payment_rails.
3. For eligible non-terminated rails (those past the 7-day grace window since last settle), dispatches settleRail(railId, currentEpoch) via SenderETH.
4. Records the tx hash on the row.

You don't have to do anything for accumulated USDFC to land in the SP wallet. The loop is autonomous.

Force a settle cycle

UPDATE harmony_task_singletons
SET run_now_request = 1
WHERE task_name = 'PDPv0_PaySettle';

The singleton scheduler picks up the flag within ~30 seconds and re-runs the task. Useful for diagnosing whether a settle is failing because of state or because the loop hasn't fired recently.

Monitor your USDFC balance

curio-core wallet list
# Lists every wallet + tFIL + USDFC balance

Or on the dashboard, the Wallets page shows live USDFC per row.

Sweep USDFC to a cold wallet

If you want to consolidate accumulated USDFC into a cold wallet:

curio-core wallet send --asset usdfc 0x<cold-wallet-address> <amount>

The send goes via SenderETH, so it's tracked in message_sends_eth and confirmed by MessageWatcherEth just like a proof tx.

Failing settlements

When a settleRail call reverts, the row's last_settle_error column captures the revert message. Common patterns:

Revert	Meaning	Action
CannotSettleFutureEpochs(railId, max, attempted)	We asked past where the account-side lockup is settled to	Expected during the 7-day grace; the next cycle will retry
RailInactiveOrSettled(railId)	Rail has nothing to claim right now	Skip; will refresh on next cycle
RailAlreadyTerminated(railId)	Rail was terminated by FWSS	Stop settling this rail; capture residual via finalization (planned)
Gas estimation revert	Usually the same future-epoch issue	Wait one cycle

The dashboard's Rails page shows a last attempt err pill when the row has a non-null last_settle_error. Hover for the full error string.

Tunables

The settle cadence + grace window is currently hard-coded:

Constant	Value	Where
PollInterval	10 minutes	internal/payments/settle.go
settleInterval	min(lockupPeriod - 1day, 7days)	per-rail computation
Override for testing	CURIO_CORE_PAYMENTS_MIN_SETTLE_EPOCHS env var	not documented for production

Production-tuning recommendations land when we see how rails behave on mainnet.