The TCV tokamak contributes to the development of nuclear fusion energy with proof-of-principle experiments and by validating models that are used to predict reactor performance. In the next upgrade of the TCV divertor it is planned to test a tightly baffled, long-legged divertor (TBLLD), a novel concept designed to enhance power exhaust handling with minimal modification to the magnetic configuration. The project is guided by simulations using the SOLPS-ITER code that indicate that a TBLLD can improve TCV’s power exhaust capability by an order of magnitude compared to its unbaffled configuration. Tight baffling sustains a high poloidal neutral density gradient along the divertor leg, thereby increasing the neutral density in front of the divertor target and enhancing volumetric power dissipation. The simulations informed the design of a proof-of-principle TBLLD for the outer TCV divertor, while ensuring compatibility with high-power plasma scenarios. A straight, vertical design, that incorporates graphite baffle tiles and is built around TCV’s reciprocating divertor probe array (RDPA), maintains engineering simplicity and enables sufficient diagnostic access. The resulting, more restrictive divertor, will also be accessible to poloidally distributed wall-mounted Langmuir probes, surface thermocouples, pressure gauges, and spectrometric lines of sight providing the measurements that will be sufficient to assess the TBLLD concept. A dedicated experimental campaign is planned for 2026