Plan a predefined benchmark case without running it. Read get_benchmark_suite for a caseId, then send requestJson containing {caseId,constraints?:{maxTaskCostUsd?,maxDurationMs?,requireMeasuredQuality?}}. Preserve every intended constraint inside requestJson; unknown and duplicate inner fields are rejected. Budget is a planning ceiling, never payment permission. Uses current published listings and exactly bound setup guides. Documented anonymous access is not a live health check, account check or guarantee that Relay has an executable adapter. Host accounts, quotas, task quality, duration and provider-billed cost remain unknown; constrained fit is unknown when measurements are absent. No ranking by invented performance, account connection, external call, automatic fallback or saved report.