Certified bounds on achievable legibility under a path cost budget
A benchmark measures what a planner achieved. This certifies what nothing could achieve: an upper bound on legibility over every admissible trajectory, not only the ones somebody tried. All 32 world and budget pairs hold with zero violations, and the narrowest gap anywhere is 0.0064.
Where it stops. The observer model is exactly reproducible and has never been validated against people, so these are bounds on a stated objective, not on what a human would infer.
Each bar runs from a trajectory that exists to a ceiling nothing can exceed. Five of the eight worlds, each at the budget where its interval is widest.