Hong Kong University of Science and Technology — path advisor rules

name: HKUST Path Advisor API — client rules
provider: Hong Kong University of Science and Technology
providerId: hkust
generated: '2026-08-30'
method: derived
source: >-
  Derived from openapi/_original/hkust-path-advisor-openapi.yml and from response behaviour
  observed live on 2026-08-30. These are rules for CONSUMING the API safely given what it
  does and does not guarantee. HKUST publishes no client guidance of its own.
x-operator: institution
rules:
  - id: name-is-required-on-nodes
    severity: error
    rule: >-
      Always send a non-empty `name` on GET /nodes. Every observed request without it — even
      one supplying floorId — returned 400 "Empty query is not allowed". There is no
      list-all-nodes route.
  - id: never-infer-existence-from-400
    severity: error
    rule: >-
      Do not treat a 400 "Bad request" as evidence that a route exists but was called wrong.
      This API returns the identical 400 body for unknown routes, so 400 is ambiguous. Only a
      200 or a distinguishing message ("Empty query is not allowed", "Authorization failed")
      proves a route is real.
  - id: coordinates-are-pixels-not-degrees
    severity: error
    rule: >-
      geoLocs is GeoJSON-SHAPED but its coordinates are floor-plan pixels, not WGS84
      longitude/latitude. Feeding these straight into a geospatial library that assumes
      degrees will silently produce nonsense. Convert using the owning Floor's meterPerPixel,
      startX and startY.
  - id: resolve-floor-before-rendering-a-node
    severity: warning
    rule: >-
      A Node is meaningless without its Floor — the floor carries the origin offset, scale
      and image dimensions its coordinates are relative to. Fetch GET /floors/{floorId}
      before plotting.
  - id: cache-reference-collections
    severity: warning
    rule: >-
      /buildings (7 items), /floors (43 items) and /tags (26 items) are small, slow-changing
      reference collections and are served with a weak ETag. Cache them and revalidate with
      If-None-Match rather than refetching per user action.
  - id: no-published-rate-limit-so-self-throttle
    severity: warning
    rule: >-
      No rate-limit headers, no 429 observed, and no published limit. Absence of a stated
      limit is not permission for volume — this is a campus service on university
      infrastructure. Keep request rates modest and back off on any 5xx.
  - id: do-not-depend-on-error-message-strings
    severity: warning
    rule: >-
      The only signal in an error is a free-text English message. It is not published, not
      versioned, and not stable. Branch on HTTP status; log the message, do not parse it.
  - id: treat-connectors-as-unavailable
    severity: info
    rule: >-
      GET /connectors returns 401 with no WWW-Authenticate header and no published enrollment
      path. Design around it rather than for it; connectorId on a Node is enough to group
      vertical circulation without it.
  - id: unversioned-contract
    severity: warning
    rule: >-
      There is no version segment in the path, no version header, and no changelog. Any field
      you depend on can change without notice. Validate responses against
      json-schema/ and fail loudly rather than silently.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com