DiagView for interactive tokamak diagnostic design and relative forward modeling

Diagnostic layout design in compact tokamaks requires engineering accessibility and expected measurement coverage to be evaluated within a consistent geometric framework. However, engineering inspection and physics-based forward modeling are commonly performed in separate workflows, making repeated design changes slow and difficult to track. We present DiagView, a web-based platform that integrates three-dimensional engineering geometry, parametric diagnostic sightlines, obstruction analysis, magnetic-equilibrium mapping, and relative synthetic signal evaluation. Using a common diagnostic configuration, the platform evaluates sightline accessibility, magnetic-surface coverage, and expected relative signals as layout parameters are adjusted. DiagView was applied to the engineering design of EHL-2. An initial comparison with normalized extreme ultraviolet measurements from the operating EXL-50U device shows that the model captures the overall spatial trend in the signal, while absolute calibration remains outside the present scope. Thus, DiagView provides a transferable workflow for integrating engineering design with physics-based diagnostic evaluation on axisymmetric tokamaks.