foundry-poc

foundry-poc is a skill for Claude Code, Codex from forefy/.context. It costs 42 tokens per session (501 once invoked), scanned A, original, MIT.

A Foundry proof-of-concept generator for EVM smart contracts. EVM is the blockchain environment used by Ethereum and compatible networks; Foundry is a toolkit that runs Solidity tests.

In plain words
What is it for?
Use it to build and verify exploit tests for security findings, including who attacks whom, how much is spent and lost, and whether the test would fail after the bug is fixed.
Why use it?
It turns a suspected smart-contract bug into a runnable test that can show whether an attacker can cause a loss of funds. It requires evidence from the actual source code.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to build and verify exploit tests for security findings, including who attacks whom, how much is spent and lost, and whether the test would fail after the bug is fixed.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/forefy/.context/foundry-poc
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 forefy/.context --skill foundry-poc
Clone the repo
git clone --depth 1 https://github.com/forefy/.context

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 foundry-poc

README.md
[![agentmods](https://agentmods.dev/badge/skills/forefy/.context/foundry-poc.svg)](https://agentmods.dev/skills/forefy/.context/foundry-poc)
Your own site
<a href="https://agentmods.dev/skills/forefy/.context/foundry-poc"><img src="https://agentmods.dev/badge/skills/forefy/.context/foundry-poc.svg" alt="Measured on agentmods" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 501 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 $0.00042 $0.00501
Opus 5 $0.00021 $0.00251
Sonnet 5 $0.00008 $0.00100
Haiku 4.5 $0.00004 $0.00050

Measured 4d ago against content hash 30c29b89bb61, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

foundry-poc 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 4d 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.

skills/blockchain/foundry-poc/SKILL.md · 41 lines

What it actually says

You are an expert smart contract security researcher. Your job is to produce verified, runnable Proof-of-Concept exploit tests for security findings - not pseudocode, not summaries. Real tests that compile, run, and prove the vulnerability exists with a passing assertion.

  • Read the actual source before writing a single line of test code.
  • Expected chain is EVM, indicated by the existence of a foundry.toml file. forge test should be compatible to tested project.

Self-questioning

  • Did the poc successfully ran, compiled, and verified the issue?
  • Are the funds lost more than the attacker spends to perform the attack?
  • Is there a clear attacker and victim?
  • Is the conclusion quantified (e.g., "attacker drained 10 ETH") not vague?
  • Do the assertions in the test actually fail if the bug is fixed?
  • Can blockchain native condition affect this attack making it unrealistic?
  • Does the usage of foundry tools like prank, do not confuse whats capable by an attacker on realistic scenario?

Proof explanation

After the test passes, add a ## Proof Explanation section as a comment in the test file:

/*
 * ## Proof Explanation
 *
 * test_PoC_F01 proves reentrancy in Vault.withdraw():
 *
 * 1. Attacker deposits 1 ETH → balance[attacker] = 1 ETH
 * 2. Attacker calls withdraw(1 ETH) → Vault sends 1 ETH via .call{}()
 * 3. Attacker's receive() fires → calls withdraw(1 ETH) again BEFORE state update
 * 4. balance[attacker] still = 1 ETH → passes require check → sends another 1 ETH
 * 5. Repeats 3 times → attacker receives 4 ETH total for 1 ETH deposit
 *
 * assertGt(vaultBefore - vaultAfter, attackerStart):
 *   Proves vault lost MORE than attacker deposited - net drain confirmed.
 *
 * assertGt(address(attacker).balance, attackerStart):
 *   Proves attacker's ETH balance grew - profit confirmed.
 */
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. 4d ago Changed · +1 lines 30c29b89bb61
  2. 8d ago First seen · 40 lines · 42 tokens per session scan A 87e4594cb381

Subscribe to this mod's changes

foundry-poc is a skill published in the GitHub repository forefy/.context (144 stars, last pushed yesterday), licensed MIT. It adds 42 tokens to every session and 501 once invoked, about $0.0002 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

asc-shots-pipeline

Orchestrate iOS screenshot automation with xcodebuild/simctl for build-run, AXe for UI actions, JSON settings and plan files, Koubou-based framing (asc screenshots frame), and screenshot upload (asc screenshots upload). Use when users ask for automated screenshot capture, AXe-driven simulator flows, frame composition…

rorkai/app-store-connect-cli-skills · 79 tokens

prompt-proximity-architecture

Turn an approved measurement charter, ICPs, and buyer jobs into a budget-aware prompt coverage blueprint across proximity bands, aided status, information acts, journey states, roles, locales, evidence grades, partitions, and measurement lanes. Use before prompt wording to define required, optional, and prohibited…

elvisun/newsjack · 67 tokens

terraform-skill

Terraform infrastructure as code best practices.

Agent-Threat-Rule/agent-threat-rules · 10 tokens

endpoint-validator

Deterministic API endpoint validation with pass/fail reporting.

notque/vexjoy-agent · 15 tokens

dev-branch-deploy

Drive the Hermes/Maia Concourse dev-branch deploy workflow — test stack changes in a live lab before merging to master. Use for "dev branch", "deploy to dev", "hermes-dev-branch", "maia-dev-branch", "test in labs", "dev lane". Covers both the hermes and maia stacks.

notque/vexjoy-agent · 76 tokens

qa-manual-istqb

Create QA artifacts from requirements: test plans, test conditions/cases, bug reports, regression suites, traceability, and exploratory charters. Use for test planning, test design, defects, coverage, or QA deliverables. Applies ISTQB risk-based techniques and loads templates only when needed. Keywords: test plan…

fugazi/test-automation-skills-agents · 84 tokens