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 $0.00009 $0.00108
Sonnet 5 $0.00004 $0.00043
Haiku 4.5 $0.00002 $0.00022

Measured 10d ago against content hash bf349c26fe13, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, 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 10d 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. 10d 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 (26 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. 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.

Related

Other skills, from other repositories

learning-from-experience

Turns incidents, near misses, bad handoffs, review surprises, escaped bugs, and signals from real use into lasting fixes to your safeguards. Use after something went wrong or nearly did and a future safeguard should change. Do not use during a live incident, which comes first, or to blame someone.

FlyFission/nuclear-grade-context-engineering · 65 tokens

reporting-shared-defects

Routes a defect found in a shared or supplied artifact (a shared prompt, skill, dependency, model, eval, or template) to the downstream teams, agents, and releases that depend on it, not just a local fix. Use when a discovered defect affects others who consume the same artifact. Do not use for a defect local to your…

FlyFission/nuclear-grade-context-engineering · 93 tokens

responding-to-incidents

Runs a live incident the stabilize-first way — name a commander, separate facts from hypotheses, prefer reversible actions, communicate on a cadence, and drive corrective actions to closure. Use when production is broken, data is at risk, or an agent action caused harm. Do not use for routine non-incident work, or as…

FlyFission/nuclear-grade-context-engineering · 80 tokens

bug-fix

Guided end-to-end bug-fix workflow for Plan Forge tempering bugs — load → pre-fix review → write failing test → fix → validate → post-fix sweep → close. Composes /code-review, /clean-code-review, /forge-quench, and /test-sweep around the forgebug tool surface so a fix never closes without a regression check.

srnichols/plan-forge · 80 tokens

forge-troubleshoot

Diagnose and resolve Plan Forge issues — failed runs, broken validation gates, misconfigured environments, stalled slices, and orchestrator errors. Use when a plan run fails or the forge behaves unexpectedly.

srnichols/plan-forge · 44 tokens

audit-loop

Run a recursive audit drain loop — discover findings from the running system, triage each into bug/spec/classifier lanes, repeat until convergence. USE FOR: end-to-end audit of a deployed or locally-running app, draining findings to zero. DO NOT USE FOR: single-shot tempering runs (use forgetemperingrun), one-off bug…

srnichols/plan-forge · 100 tokens