mev-protection-guide

mev-protection-guide is a skill for Claude Code, Codex from nirholas/three.ws. It costs 52 tokens per session (1,255 once invoked), scanned A, original, Apache-2.0.

A guide to MEV, the profit traders and block producers can make by changing the order of blockchain transactions. It explains sandwich attacks, frontrunning, backrunning, and related risks for decentralised exchange swaps.

In plain words
What is it for?
Explaining MEV, recommending swap-protection approaches, and examining suspicious transaction patterns.
Why use it?
It helps identify when a transaction may be exploited and explains ways to reduce losses caused by transaction reordering and high slippage settings.

Skill for Claude CodeCodex

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 skills/nirholas/three.ws/mev-protection-guide
Any agent
npx skills add nirholas/three.ws --skill mev-protection-guide
Clone the repo
git clone --depth 1 https://github.com/nirholas/three.ws

Made for: Claude Code, Codex.

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 mev-protection-guide

README.md
[![agentmods](https://agentmods.dev/badge/skills/nirholas/three.ws/mev-protection-guide.svg)](https://agentmods.dev/skills/nirholas/three.ws/mev-protection-guide)
Your own site
<a href="https://agentmods.dev/skills/nirholas/three.ws/mev-protection-guide"><img src="https://agentmods.dev/badge/skills/nirholas/three.ws/mev-protection-guide.svg" alt="Measured on agentmods" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,255 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 5.1 $0.00052 $0.01255
Opus 5 $0.00026 $0.00628
Sonnet 5 $0.00010 $0.00251
Haiku 4.5 $0.00005 $0.00126

Measured 2d ago against content hash b1f15c72c860, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

mev-protection-guide 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.

data/skills/security/mev-protection-guide/SKILL.md · 147 lines

How it starts

The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MEV Protection Guide

MEV (Maximal Extractable Value) is profit that block builders and searchers extract by reordering, including, or excluding transactions. Understanding MEV helps protect your users' trades.

Types of MEV

1. Sandwich Attacks

The most common MEV attack on DEX swaps:

1. Attacker sees your swap in mempool
2. Attacker buys before you (frontrun) → pushes price up
3. Your swap executes at a worse price
4. Attacker sells after you (backrun) → profits from the price difference

Who gets hurt: Anyone swapping on DEXs with high slippage tolerance Typical loss: 0.3–2% of trade value

2. Frontrunning

A searcher copies your profitable transaction and submits it first with higher gas:

  • Arbitrage opportunities
  • NFT mints
  • Liquidation calls

3. Backrunning

Searcher submits a transaction immediately after yours to capture resulting arbitrage:

  • After large swaps (price impact creates arb opportunity)
  • After oracle updates
  • After liquidations

4. Just-In-Time (JIT) Liquidity

A sophisticated attack on V3 pools:

  1. Searcher adds concentrated liquidity just before your swap
  2. Your swap pays fees to the searcher's position
  3. Searcher removes liquidity immediately after

5. Time-Bandit Attacks

Block proposers reorganize past blocks to capture MEV. Rare but possible with proof-of-stake.

Protection Strategies

For Users

Strategy Protection Level Tradeoff
Low slippage (0.5%) Medium May fail on volatile tokens
Private mempool High May have slight delay
DEX aggregator Medium–High Best price routing
Limit orders High No immediate execution

1. Use Low Slippage Tolerance

Set slippage to 0.5% or lower. This limits how much the price can move against you, making sandwich attacks unprofitable.

Caution: Too-low slippage on volatile tokens may cause transactions to fail.

2. Private Transaction Submission

Send transactions through private mempools that hide them from searchers:

Read the full file on GitHub · 147 lines

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 · 147 lines · 52 tokens per session scan A b1f15c72c860

Subscribe to this mod's changes

mev-protection-guide is a skill published in the GitHub repository nirholas/three.ws (110 stars, last pushed today), licensed Apache-2.0. It adds 52 tokens to every session and 1,255 once invoked, about $0.0003 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 2026-09-03.

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