TYPE 0x0661 · PLC FAMILY

ONE_SHOT

One-shot trigger. SATISFIED when the state is armed (state == 0). Once fired (state != 0), permanently becomes UNSATISFIED. Commits to a HASH256 for binding the trigger to a specific action. No Tapscript equivalent exists.

PLC Invertible

Ladder Diagram

Fields

Field	Data Type	Size	Side	Description
state	NUMERIC	1-4 B	Conditions	Trigger state: 0 = armed (can fire), nonzero = fired (permanently used)
commitment	HASH256	32 B	Conditions	Commitment hash binding the trigger to a specific action or context

No witness fields required. The HASH256 commitment binds the one-shot to a specific purpose, preventing reuse across different contexts.

Wire Format Breakdown

0x0661 0 2 NUMERIC · 3B HASH256 · 32B Conditions = 43 bytes

0x0661 0 0 Witness = 4 bytes (empty block)

Total 47 bytes

Evaluation Logic

1.Read state from NUMERIC field. If missing → ERROR

2.Read commitment from HASH256 field. If missing → ERROR

3.If state == 0 → SATISFIED (trigger is armed, can fire)

4.If state != 0 → UNSATISFIED (trigger already fired, permanently used)

Return Values

Condition	Result
Missing NUMERIC field	ERROR
Missing HASH256 commitment	ERROR
state != 0 (already fired)	UNSATISFIED
state == 0 (armed)	SATISFIED

JSON Wire Format

Conditions (armed, with commitment)

{
  "type": "ONE_SHOT",
  "inverted": false,
  "fields": [
    { "type": "NUMERIC", "value": 0 },
    { "type": "HASH256", "hex": "a1b2c3d4...commitment hash...32 bytes" }
  ]
}

This creates an armed one-shot trigger. Once the state transitions to any nonzero value in the covenant chain, the trigger permanently disables.

Worked Example

commitment=0xabcd...1234

state=0: armed → SATISFIED (can fire)

state=1: fired → UNSATISFIED (permanently used)

state=255: fired → UNSATISFIED (any nonzero = fired)

No NUMERIC field: → ERROR

Use Cases

Single-Use Authorizations

Grant a one-time spending permission that permanently expires after use. The covenant output carries the trigger state, ensuring the authorization cannot be replayed in subsequent spends.

One-Time Unlocks

Create a covenant path that can only be taken once. Combined with other blocks, enables single-use emergency overrides, one-time key rotations, or irrevocable state transitions.

Non-Repeatable Actions

Enforce that a specific action (bound by the HASH256 commitment) can only occur once in a covenant chain. Prevents double-spending of vouchers, duplicate claim attempts, or repeated initialization.

← SEQUENCER RATE_LIMIT →