Some nodes can only be connected to the Fragment stage. The Is Front Face node uses the SV_IsFrontFace semantic which is only available as an input to the fragment shader. This should make sense, as the vertex shader runs on vertices - which do not have any information about how they connect or the faces yet. Partial screen space derivative functions (DDX, DDY, DDXY) are also only supported by the fragment shader, as they compare values for neighbouring fragments/pixels. Shader Graph does not make this problem very clear, but it is most commonly encountered when dealing with the Sample Texture 2D node, which uses these derivatives behind the scenes to calculate the mipmap level when sampling. You would instead need to use the Sample Texture 2D LOD version. There are other nodes that rely on the derivates, such as Normal From Height and the various procedural shapes (e.g. Ellipse, Rectangle, Polygon, Rounded Rectangle, Rounded Polygon). There are also nodes that use SAMPLE_TEXTURE2D(tex, sampler, uv) in their code (e.g. Triplanar), but these could likely be rewritten manually via a Custom Function node to use the SAMPLE_TEXTURE2D_LOD(tex, sampler, uv, lod) macro instead, in order to support the vertex shader. (Can view generated code for a specific node by right-clicking it and selecting Show Generated Code or Open Documentation) For more information / nodes affected, see Intro to Shader Graph post - Fragment-Only Nodes