rules-location

A set of rules for where Cursor stores its rule files and how those Markdown files should be named. Cursor is a code editor with AI features, and MDC files are its rule files.

In plain words
What is it for?
Use it when creating, locating, naming, or troubleshooting Cursor rule files.
Why use it?
It reduces confusion when rules are not found, are saved in the wrong folder, or use an invalid name.

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/fiddike/cursor-rules-mdc/rules-location
Clone the repo
git clone --depth 1 https://github.com/fiddike/Cursor-Rules-MDC

Made for: Cursor.

Per session 1,612 This file is loaded in full into every session.
When invoked 1,612 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.01612 $0.01612
Opus 5 $0.00806 $0.00806
Sonnet 5 $0.00322 $0.00322
Haiku 4.5 $0.00161 $0.00161

Measured yesterday against content hash 99069b1f71fd, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

rules-location 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/rules-location.mdc · 213 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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 · 213 lines · 1,612 tokens per session scan A 99069b1f71fd

Subscribe to this mod's changes

rules-location is a cursor rule published in the GitHub repository fiddike/Cursor-Rules-MDC (2 stars, last pushed 1y ago), with no licence file. It adds 1,612 tokens to every session, about $0.0081 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.