core

Project-wide rules for a Sanity and React codebase. They define how to reuse modules, handle languages, regenerate types, and validate schema changes.

In plain words
What is it for?
Use them for any project change, especially new content modules, localized rendering, schema updates, type checks, and formatting.
Why use it?
They prevent incomplete module wiring, incorrect localization, and edits to generated files that would be overwritten.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/backendforth/next-sanity-starter/core
Clone the repo
git clone --depth 1 https://github.com/backendforth/next-sanity-starter

Made for: Cursor.

Per session 214 This file is loaded in full into every session.
When invoked 214 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00214 $0.00214
Opus 5 $0.00107 $0.00107
Sonnet 5 $0.00043 $0.00043
Haiku 4.5 $0.00021 $0.00021

Measured yesterday against content hash 7365cb9c8423, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

core scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/core.mdc · 15 lines

What it actually says

Canonical guardrails: /AGENTS.md. Read it before writing code in this repo.

Top-level rules (do not duplicate — see AGENTS.md for the full context):

  • Reuse before invention; grep studio/schemas/objects/modules/, web/src/components/modules/, web/sanity/queries/snippets/ first.
  • Content blocks are modules — paired Sanity object + React component, wired in 8 places. Skipping any one is a bug.
  • Locale-aware at render time, never inside GROQ. Always use pickLocalizedString / parseLocalizedText from web/sanity/utils/sanityLocalizedText.ts.
  • After schema edits: pnpm studio:generatepnpm typecheckpnpm format. Never edit studio/sanity.types.gen.ts or studio/schema.json.
  • web/sanity/types/* are hand-maintained; keep aligned with field changes.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 15 lines · 214 tokens per session scan A 7365cb9c8423

Subscribe to this mod's changes

core is a cursor rule published in the GitHub repository backendforth/next-sanity-starter (4 stars, last pushed 25d ago), licensed ISC. It adds 214 tokens to every session, about $0.0011 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.