cursorrules

A rule for Cursor, an AI coding editor, that requires a specific Effect-Patterns search tool whenever someone asks about Effect-TS patterns or how to do something in Effect. It forbids searching pattern files directly with filesystem tools.

In plain words
What is it for?
Use it when handling Effect-TS pattern requests in Cursor, where the required pattern-search tool must be used.
Why use it?
It ensures pattern questions use the designated source and that its results are shown without rewriting them.

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/pauljphilp/effectpatterns/cursorrules
Clone the repo
git clone --depth 1 https://github.com/PaulJPhilp/EffectPatterns

Made for: Cursor.

Per session 275 This file is loaded in full into every session.
When invoked 275 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 $0.00275 $0.00275
Opus 5 $0.00138 $0.00138
Sonnet 5 $0.00055 $0.00055
Haiku 4.5 $0.00028 $0.00028

Measured yesterday against content hash 4129321b16c4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cursorrules 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.

.cursorrules · 26 lines

What it actually says

Cursor Rules

HARD CONSTRAINT: Pattern Tool Usage

CRITICAL RULE: If the user mentions "patterns", asks "how to" in Effect, or requests Effect-TS guidance, you are FORBIDDEN from using filesystem tools to find patterns.

FORBIDDEN Tools for Pattern Queries:

  • grep - Never search pattern files
  • read_file - Never read pattern files directly
  • codebase_search - Never search codebase for patterns
  • glob_file_search - Never search for pattern files
  • list_dir on pattern directories - Never browse pattern directories

REQUIRED Tool for Pattern Queries:

  • mcp_Effect-Patterns-effect-patterns_search_patterns - MUST use this tool
  • ✅ Display results verbatim - DO NOT summarize or rewrite

Why This Rule Exists:

  • The search_patterns tool provides production-tested code and rich-UI blocks
  • Manual file searching misses critical context, examples, and structured guidance
  • Pattern files contain implementation details that should not be exposed directly
  • The MCP tool ensures consistent, authoritative pattern presentation

Violation Consequences:

Manual summarization of pattern files is a violation of project safety standards. Always use the authorized MCP tool.

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 · 26 lines · 275 tokens per session scan A 4129321b16c4

Subscribe to this mod's changes

cursorrules is a cursor rule published in the GitHub repository PaulJPhilp/EffectPatterns (794 stars, last pushed 2mo ago), licensed MIT. It adds 275 tokens to every session, about $0.0014 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 2026-08-30.