`withIdempotency` has made writes safe to retry since v1.5.x. It was described
in route comments and in no schema, so an app generated against
`docs/api/openapi.yaml` could not learn that a retry was safe. The iOS side
asked for it; the mechanism does not change, only what it says about itself.
34 operations now declare `Idempotency-Key` and the `X-Idempotent-Replay`
header, plus the 409 that refuses a duplicate still in flight. The description
leads with the one silent failure in the mechanism: a key that misses
`^[A-Za-z0-9_\-:.]{8,128}$` is IGNORED rather than refused, so the write
proceeds unprotected and looks exactly like a request that carried no key.
## What the work turned up
Three things the contract had wrong or missing, none of them the thing being
built:
- `/api/insights/chat` describes `withIdempotency()` in its header comment and
applies it nowhere. The Coach chat is not retry-safe. Its prose says it is.
- `/api/measurements` exports GET, POST, PUT and DELETE and wraps only POST.
Publishing the header per PATH would have promised a safe retry on two
methods that do not honour one — the dangerous direction, so the guard works
per OPERATION.
- `/api/insights/feedback` and `/api/admin/backups/{id}/restore` are not in the
document at all. Both are named in the guard's exemption list with a reason,
not filtered out silently.
## The guard
`idempotency-contract-publication.test.ts` reads the expected set out of the
route tree on every run — nothing is hand-listed, so it cannot fall behind the
code. It fails in both directions: a new wrapped route that forgets to publish,
and a published claim no handler honours.
A fourth assertion checks the exemption list itself is still true. It earned
its place immediately: the first draft exempted the whole `/api/medications`
family on the strength of a grep for path literals that came back empty. The
paths are not written as literals there; the emitted document carries 19 of
them. The test went red, the claim was wrong, the list is two entries now.
Measure the artefact, not the source that builds it.
Every route that resolves a record through the sharing fence can answer 403
`sharing.access.denied`, and until now that fact was published on the selector
header and on none of the 120 operations that produce it. All 120 carry it now,
byte for byte, from one constant: the refusal is deliberately indistinguishable
across a missing account, a missing grant, a scope that does not reach the
surface and a read grant on a write, so 120 paraphrases would invite a client to
tell apart what the server refuses to.
Where a delegable route already answered 403 for its own reason — a module
gate, the cycle gate, AI consent — the two share one description rather than one
of them going unpublished, since OpenAPI allows a single response per status.
The guard recomputes the delegable set from the route sources on every run and
classifies per verb, which matters: seventeen modules have a delegable read
beside a write that refuses a switch outright.
NutrientIntakeDay's composite primary key gains `source` (migration
0249_nutrient_intake_day_source): a manual water entry and the
Apple-synced day total now live as two rows instead of the manual
write being silently clobbered by the next Apple last-writer-wins
sync. Every existing row already defaults to source=APPLE_HEALTH, so
the migration is a pure PK-constraint change with no data rewrite.
- POST /api/nutrients/batch keeps writing the APPLE_HEALTH row,
byte-identical upsert semantics against the wider key.
- GET /api/nutrients sums amounts within (nutrient, day) across
sources before folding into the window summary.
- POST /api/nutrients/water (new): manual water quick-add, add/set
modes against the MANUAL row only, module-gated, rate-limited,
idempotency-key aware, hard-evicts the dashboard snapshot cache.
- GET /api/nutrients/daily (new): dense per-day series for one
nutrient (summed across sources) plus the EFSA reference resolved
against the caller's profile sex — omitted when sex is unknown.
- catalog.ts gains resolveNutrientReference(), the sex-resolution
helper both new routes and the insights cards share.
docs/api/openapi.yaml regenerated for the two new routes.
Supplement-style intake written to Apple Health by nutrition apps —
vitamins, minerals, water, caffeine — can now sync as daily totals into a
dedicated NutrientIntakeDay store (migration 0241): composite (user, day,
nutrient) identity, re-post replaces, no soft delete, no rollup coupling.
A code-side catalog carries the 26 nutrient codes with canonical units,
plausibility caps, and EFSA dietary reference values (direction-aware;
chromium cites NIH ODS where EFSA declined a DRV).
Deliberately not a nutrition feature: no diary, no calories, no dashboard
surface. POST /api/nutrients/batch is gated behind the new opt-in
nutrients module (default off — with the module off the server refuses
ingest entirely), rate-limited, idempotency-wrapped, with per-entry
unit-mismatch and out-of-range skips. GET /api/nutrients serves a
catalog-ordered summary; the only visible surface is a read-only card
under Settings → Sources. Coach/correlation access is a later slice; the
iOS reading side is coordinated in the companion-app tracker.
Marc-André Bombeck