Domain model¶

The domain answers one question — should the loop run, wait, or stop right now? — from values, not I/O:

• Capacity ADT — a verdict on whether the vendor can take another turn: available, rate-limited (a waitable window), or exhausted credits (not waitable). Classification is driven by the billing and rate-limit lexicons from configuration, so a vendor's new error phrasing is a config change.
• Waiting policy — a bounded probe: waits carry a deadline (max_wait_seconds), never an open-ended sleep.
• Budget ledger — every turn's cost accrues against max_dollars; the ledger stops the run before an overrun, not after.
• Completion verdicts — the fence/marker/reconciliation evidence (see completion detection) reduced to one typed verdict.
• Run-loop state machine — the states and transitions in run-loop.md, consuming the values above.

Everything here is a frozen dataclass or an enum, so a transition is a fact you can assert in a test.