Instruction file imported from humanaxiom/SFU-digital-twin (.github/instructions/accessibility-claims.instructions.md). Copyright stays with the author.

Accessibility claims

• The source geodatabase has no path-level accessibility attributes (no width, slope, surface, door-power data — see docs/01-data-findings.md gaps G1–G3).
• The only honest accessible-routing rule this data supports is: exclude every edge with mode = stairs; route only over pathways and TRANSITION_TYPE = 4 (elevator) edges — see docs/02-system-design.md §4.2.
• Never phrase an accessible route as "wheelchair-certified" or imply a stronger guarantee than "elevator-only, stairs excluded." Surface the not_verified list (door_width, path_width, slope, powered_doors, surface) alongside any accessibility claim in an API response or UI string.
• Any field that drives an accessibility decision must carry verified_by and verified_date. Unknown must never default to accessible — default to the more conservative (non-accessible) assumption.
• If no step-free path exists, the correct behavior is an explicit failure (e.g. HTTP 409 with reachable levels and nearest elevator) — never a silent fallback to a stairs route.