Runner is the in-situ execution engine that lives inside the custodian's boundary. It receives signed UQL, executes against the local OMOP, returns aggregate-only results, and logs every step. No patient-level data ever crosses the wall.
Runner has no outbound path for patient-level data. Its only egress is the signed aggregate result. Reviewed, penetration-tested, and independently assessable — the whitepaper is available on request.