Production-shaped Next.js 16 + Sanity Studio v5 starter with locale routing, Mux video, Visual Editing, and AI-agent guardrails. Two i18n flavours.
3 files for GitHub Copilot, Codex, OpenCode and Claude Code: next-sanity-starter copilot-instructions.md, next-sanity-starter AGENTS.md, next-sanity-starter CLAUDE.md — 9,498 tokens loaded in every session.
.github/copilot-instructions.md A 359 tok AGENTS.md A 9,015 tok CLAUDE.md A 124 tok These files are backendforth/next-sanity-starter's own configuration — they tell GitHub Copilot, Codex, OpenCode and Claude Code how to work on this repository, so they are not mods to install elsewhere. Copy one as a starting point and replace the parts that are about this project.