where_woof/openspec/changes/sms-metering-location-link/specs/sms-metering/spec.md

ADDED Requirements

Requirement: Per-tag SMS credits

Each tag SHALL track sms_allocated, sms_used, and sms_period_start. An allocation of 0 SHALL mean unmetered (no credit limit).

Scenario: Allocated plan

• WHEN an admin sets sms_allocated = 10 on a tag
• THEN the tag may send up to 10 SMS in the period

Scenario: Unmetered default

• WHEN a tag has sms_allocated = 0
• THEN credit checks do not apply (transitional behaviour)

Requirement: Credits required to send

Before sending an alert or finder-contact SMS on a metered tag, sms_used < sms_allocated SHALL hold. Each successful send SHALL increment sms_used. When exhausted, scans are recorded but no SMS is sent.

Scenario: Send consumes a credit

• WHEN an alert SMS is sent on a metered tag
• THEN sms_used increments by one

Scenario: Credits exhausted

• WHEN sms_used >= sms_allocated on a metered tag
• THEN further scans record but no SMS is sent