MCP backend Use when: Any material assignment, PBR setup, shader work, or look-dev request in Blender. Before the first Blender call, read ../text-to-blender/references/mcp-backends.md. Prefer official MCP for shared capabilities; preserve the selected backend for the whole task. Tool names in recipes are client/legacy examples: map them through that reference and its agent-host guide. Blender Materials Apply physically-based materials to objects. Use only Principled BSDF — it's the only shader that exports cleanly to glTF and matches what other DCC tools expect. The metallic switch — never a…