`GET /api/sync/changes` returns five domains — measurements, mood, intakes, cycleDays, cycles — and has since the cycle module landed. The registered schema declared three, closed the object and required only those three, so `cycleDays` and `cycles` did not exist in the contract: full day-log and cycle payloads, both upserts and tombstones, computed and serialised on every single pull, invisible to any client generated from the spec. The body was also invalid against its own schema, since the object was closed against the two keys it always sends. The day-log and cycle DTOs were already published for the cycle routes, so the two upsert arrays reuse them and only the tombstone shapes are new. The module's own description and the operation summary were stale in the same direction and now name all five. This is the two-ended change the contributor notes describe: the writer shipped, the contract half did not, and no gate noticed because every gate proves the other end. No wire change.
HealthLog API Spec
openapi.yaml is the OpenAPI 3.1 description for the HealthLog
Next.js API and the source of truth for the native iOS client's DTO
codegen. The file is generated: pnpm openapi:generate emits it
from the Zod registry under src/lib/openapi/ (registry.ts plus the
route modules in src/lib/openapi/routes/). Do not edit the YAML by
hand; the next generation overwrites it, and CI (openapi:check)
fails the build when the committed YAML drifts from the registry.
The MCP server is documented separately — it is a distinct contract over JSON-RPC, not part of the REST OpenAPI spec:
mcp-capabilities.md— the tool, resource, and prompt catalogue, the grounding contract, and the write model.mcp-skills.md— building a connector or skill on top of it.../self-hosting/mcp.md— enabling and connecting the surface (operator guide).
Preview locally
Open an interactive Redoc preview in your browser:
npx @redocly/cli preview docs/api/openapi.yaml
Generate static HTML for sharing:
npx @redocly/cli build-docs docs/api/openapi.yaml --output docs/api/index.html
Validate
npx @redocly/cli lint docs/api/openapi.yaml
The spec is expected to be lint-clean (errors = 0). Warnings such as
no-server-example.com for the localhost dev server are tolerated;
re-run the lint to see what it produces against the current file
before treating a warning as a regression.
Layout
info— title, description, andversionmirrored automatically frompackage.jsonat generation time. Never bump it by hand.servers—https://healthlog.example.comas the self-hosted placeholder plushttp://localhost:3000for local development.tags— domain groupings; the current set lives at the top of the generated file (Auth,Measurements,Medications,Mood,Analytics,Insights,Consent,Dashboard,Notifications,Devices,Export,Sync,Cycle,MeasurementReminders,Labs,Illness,Documents,Records,Admin,Meta,Retired).securitySchemes:-
bearerAuth—hlk_*API tokens. A scope grants what it names and nothing adjacent, so where a token comes from decides what it reaches:- a completed password / passkey / refresh exchange mints the
cookie-equivalent
["*"]token the native client carries; - a medication's own API-endpoint toggle mints
medication:ingestplusmedication:<id>:ingest, the pair/api/ingest/medicationgates on; POST /api/mcp/tokensmintshealth:read(optionally plushealth:write), audience-bound to/mcpand refused on REST writes;POST /api/tokens/measurementsmintsmeasurements:write, accepted byPOST /api/measurementsandPOST /api/measurements/batchonly, on the holder's own record only.
POST /api/tokensis not among them — that generic mint was removed in v1.30.17. The path still lists (GET) and revokes (DELETE /api/tokens/{id}) every token above, whichever surface issued it. - a completed password / passkey / refresh exchange mints the
cookie-equivalent
-
sessionCookie— HttpOnlyhealthlog_sessioncookie set by the password and passkey login flows. Used by the web app and any iOS client running inside a web view.
-
components.schemas— DTOs for the documented routes plus the underlying Prisma models (e.g.Measurement,Medication,MedicationIntakeEvent,MoodEntry,User,DashboardLayout,ApiEnvelope,ApiError).paths— the client-facing REST surface. Not everysrc/app/api/**/route.tsis in the contract: most/api/admin/*routes, the OAuth connect/callback legs, and the webhook surfaces are not documented here. TheRetiredtag lists removed paths that answer410 Gone.
Conventions
- Successful responses use the envelope
{ data, error: null }. - Error responses use the envelope
{ data: null, error: '<message>' }. - Pagination uses
limit+offsetquery parameters and ameta: { total, limit, offset }block on the response. - All timestamps are ISO 8601 / RFC 3339 (
format: date-time) in UTC. - IDs are CUIDs (opaque strings).
Updating the spec
When adding or changing routes:
- Update the relevant route handler under
src/app/api/**/route.ts. - Change the Zod schemas and their
.meta()registrations undersrc/lib/openapi/(registry entry plus the matching module insrc/lib/openapi/routes/). KeepoperationIdcamelCase and stable; the iOS codegen keys off it. - Run
pnpm openapi:generateand commit the regeneratedopenapi.yamlalongside the schema change. CI'sopenapi:checkfails on drift. - Never edit the YAML directly and never bump
info.versionby hand; the version followspackage.jsonat generation time.