prevention-rules

prevention-rules is a skill for Cursor from IgorGanapolsky/ThumbGate. It costs 18 tokens per session (216 once invoked), scanned A, original, MIT.

A system for creating and reviewing prevention rules based on repeated failure patterns in a project.

In plain words
What is it for?
Use it to list active rules, test actions against them, inspect the feedback behind a rule, and generate new rules from repeated failures.
Why use it?
It can explain why a proposed action is blocked and help stop the same mistake from recurring.

Skill for Cursor

Written for Cursor: shipped in a Cursor plugin.

Part of the thumbgate plugin — 5 skills, 3 commands, 2 agents shipped together

Good fit Use it to list active rules, test actions against them, inspect the feedback behind a rule, and generate new rules from repeated failures.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/igorganapolsky/thumbgate/prevention-rules
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.

Any agent
npx skills add IgorGanapolsky/ThumbGate --skill prevention-rules
Clone the repo
git clone --depth 1 https://github.com/IgorGanapolsky/ThumbGate

Made for: Cursor.

Or install thumbgate, the plugin that ships this one along with the rest of its 5 skills, 3 commands, 2 agents.

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.

agentmods badge for prevention-rules

README.md
[![agentmods](https://agentmods.dev/badge/skills/igorganapolsky/thumbgate/prevention-rules/github.svg)](https://agentmods.dev/skills/igorganapolsky/thumbgate/prevention-rules)
Your own site
<a href="https://agentmods.dev/skills/igorganapolsky/thumbgate/prevention-rules"><img src="https://agentmods.dev/badge/skills/igorganapolsky/thumbgate/prevention-rules/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.

agentmods 80×15 button for prevention-rules

Your own site · 80×15
<a href="https://agentmods.dev/skills/igorganapolsky/thumbgate/prevention-rules"><img src="https://agentmods.dev/badge/skills/igorganapolsky/thumbgate/prevention-rules.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 18 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 216 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00018 $0.00216
Opus 5.5 $0.00007 $0.00086
Sonnet 5.5 $0.00004 $0.00043
Haiku 4.5 $0.00002 $0.00022

Measured 1mo ago against content hash bf349c26fe13, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

prevention-rules 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 1mo 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.

plugins/cursor-marketplace/skills/prevention-rules/SKILL.md · 32 lines

What it actually says

Prevention Rules

Manage prevention rules that are auto-generated from repeated failure patterns.

When to use

  • Reviewing current active prevention rules for the project
  • Checking if a specific action is blocked by a prevention rule
  • Understanding why an action was blocked
  • Generating new prevention rules from observed patterns

How it works

Use the prevention_rules MCP tool to:

  1. List rules — View all active prevention rules with their match patterns and corrective actions.
  2. Check rules — Test if a specific action matches any prevention rule before execution.
  3. Review rule history — See which feedback events led to a rule's promotion.

Example

Check prevention rules for "npm publish without running tests" to see if this action is blocked.

Prevention rules are auto-promoted when the same failure pattern appears multiple times in captured feedback. Each rule includes the original failure context and a corrective action.

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. 1mo ago First seen · 32 lines · 18 tokens per session scan A bf349c26fe13

Subscribe to this mod's changes

prevention-rules is a skill published in the GitHub repository IgorGanapolsky/ThumbGate (29 stars, last pushed today), licensed MIT. It adds 18 tokens to every session and 216 once invoked, about $0.0001 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 2026-08-30.

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