Two things the plan's own text asked back. First, the idempotency-key
comment lost its substance when Task 5 rewrote it: the charged amount and
the treatment are in the key because at a rate of nought the two Prices
are the same amount and one key would have Stripe hand back a single
object for both — a maintainer who simplified that key would only
rediscover why from a unique-constraint violation. Restored alongside the
newer sentence about what actually stops a second Price (adoption, not
this key), so the module and plan sides read alike again. Spelled out
"twenty-four hours" in both places in the same comment, matching the
sibling.
Second, nothing pinned identifying: ['plan_price_id'] — the one decision
that makes the plan side different from the module side, because a
family's Product carries a Price for every version, term and treatment,
so plan_family alone cannot say which row a Price belongs to. Added a
test that plants a Price proving only the family, confirmed it fails
when identifying is loosened to ['plan_family'], and reverted.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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