ruby-regex-delimiter

A Ruby style rule for writing regular expressions that contain forward slashes.

In plain words
What is it for?
It is for choosing Ruby's %r{...} syntax instead of slash-delimited syntax when a pattern includes slashes.
Why use it?
It reduces the escaping needed inside patterns, making them easier to read.

Cursor rule

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/panozzaj/cursor-rules/ruby-regex-delimiter
Clone the repo
git clone --depth 1 https://github.com/panozzaj/cursor-rules
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 142 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00000 $0.00142
Opus 5 $0.00000 $0.00071
Sonnet 5 $0.00000 $0.00028
Haiku 4.5 $0.00000 $0.00014

Measured 2d ago against content hash dace47fb9857, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ruby-regex-delimiter 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 2d 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.

rules/ruby-regex-delimiter.mdc · 25 lines

What it actually says

Use %r{} for Ruby Regex Literals Containing Slashes

When a regular expression literal contains one or more forward slashes (/), use the %r{...} syntax instead of the default /.../ syntax.

This improves readability by avoiding the need for excessive escaping of the forward slash character within the regex pattern.

Good:

pattern = %r{/some/path/}

Bad:

pattern = /\/some\/path\//

Note that printing off regular expressions may still have escaped slashes.

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. 2d ago First seen · 25 lines · 142 tokens per session scan A dace47fb9857

Subscribe to this mod's changes

ruby-regex-delimiter is a cursor rule published in the GitHub repository panozzaj/cursor-rules (3 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 142 tokens. 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.