What is express-rule?

A set of Cursor instructions covering project structure, middleware, performance, coding conventions, and testing. Middleware is code that runs between a request and the part of an application that handles it.

It is for organizing an Express project, using middleware, improving performance, following coding standards, and testing code.

It gives an agent project-specific guidance for writing and checking Express applications consistently.

express-rule — Cursor rule for Cursor by leonardogrig

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.

Clone the repo

git clone --depth 1 https://github.com/leonardogrig/cursor-rules-generator-api

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/rules/leonardogrig/cursor-rules-generator-api/express-rule/github.svg)](https://agentmods.dev/rules/leonardogrig/cursor-rules-generator-api/express-rule)

Your own site

<a href="https://agentmods.dev/rules/leonardogrig/cursor-rules-generator-api/express-rule"><img src="https://agentmods.dev/badge/rules/leonardogrig/cursor-rules-generator-api/express-rule/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/rules/leonardogrig/cursor-rules-generator-api/express-rule"><img src="https://agentmods.dev/badge/rules/leonardogrig/cursor-rules-generator-api/express-rule.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 5 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 2,950 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00005	$0.02950
Opus 5.5	$0.00002	$0.01180
Sonnet 5.5	$0.00001	$0.00590
Haiku 4.5	$0.00001	$0.00295

Measured 2mo ago against content hash 426cf9d1dc5a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

express-rule 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 2mo ago.

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/express-rule.mdc · 344 lines

The source is not reproduced here

No licence file

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.

2mo ago First seen · 344 lines · 5 tokens per session scan A 426cf9d1dc5a

Subscribe to this mod's changes

express-rule is a cursor rule published in the GitHub repository leonardogrig/cursor-rules-generator-api (5 stars, last pushed 1y ago), with no licence file. It adds 5 tokens to every session and 2,950 once invoked, about $0.0000 per session on Opus 5.5. 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.

express-rule next to 6 cursor rules from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
express-ruleleonardogrig/cursor-rules-generator-api	Cursor rule	5	1y ago	none	A	5	Cursor
ponytailDietrichGebert/ponytail	Cursor rule	186k	9d ago	MIT	A	604	Cursor
angular-20angular/angular	Cursor rule	101k	today	MIT	A	0	Cursor
dev-standardapache/superset	Cursor rule	75k	today	Apache-2.0	A	1,147	Cursor
control-plane-descriptorsprisma/orm	Cursor rule	48k	yesterday	Apache-2.0	A	0	Cursor
family-instance-domain-actionsprisma/orm	Cursor rule	48k	yesterday	Apache-2.0	A	0	Cursor
prefer-assertions-over-defensive-checksprisma/orm	Cursor rule	48k	yesterday	Apache-2.0	A	0	Cursor