Buys a fixed dollar amount of one token on a schedule, and nothing else.

Each fire buys SIZE_USD of TOKEN at whatever the price is, then leaves a quiet note in the duty's thread. Dollar-cost averaging: the same size every time, so the size is the decision and the timing is not.

What it will not do

• Look at the price. There is no dip check, no condition, no "only if". An owner who wants one is asking for a different duty — a timer whose code fetches the figure itself and decides.
• Buy twice for one slot. Every buy is keyed on the schedule slot, not the instant it fired, so a catch-up after a restart and the fire it is catching up on are one buy. The ledger answers the second one replay.
• Sell, ever. It only buys.
• Spend before the owner funds it. It spends through the pocket, which starts empty; until it is funded every buy becomes an approval card. Once funded, the pocket is the only limit on what it spends: the duty keeps no daily count of its own, and the server refuses a buy the pocket can't cover.

Settings

Name	Unit	Default	Means
TOKEN	address or symbol	required	what to buy. An address is exact; a bare symbol is resolved by the rail and may land on a wrapper
SIZE_USD	US dollars per buy	required	minimum 2 — the swap route's own floor, below which the leg comes back as a wire error
CHAIN_ID	chain id	unset	which chain to buy on. Omit to let the rail choose
SIZING	—	fixed	fixed-size by definition; it takes no other value

TOKEN and SIZE_USD are the only two an owner must decide. CHAIN_ID is worth setting only when they named a chain.

Trigger

One timer — either a time of day in the owner's zone, or an interval:

{ "kind": "timer", "dailyAt": "09:00", "timezone": "Asia/Singapore" }

A dailyAt whose slot has already passed today fires today.