Borrowing it
Nothing to install: this file belongs to Hirama/solidity-agentic-stack. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/Hirama/solidity-agentic-stack/main/.claude/skills/foundry-cheatcodes/SKILL.mdgit clone --depth 1 https://github.com/Hirama/solidity-agentic-stackWrote 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.
[](https://agentmods.dev/skills/hirama/solidity-agentic-stack/foundry-cheatcodes)<a href="https://agentmods.dev/skills/hirama/solidity-agentic-stack/foundry-cheatcodes"><img src="https://agentmods.dev/badge/skills/hirama/solidity-agentic-stack/foundry-cheatcodes/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.
<a href="https://agentmods.dev/skills/hirama/solidity-agentic-stack/foundry-cheatcodes"><img src="https://agentmods.dev/badge/skills/hirama/solidity-agentic-stack/foundry-cheatcodes.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00070 | $0.01620 |
| Opus 5.5 | $0.00028 | $0.00648 |
| Sonnet 5.5 | $0.00014 | $0.00324 |
| Haiku 4.5 | $0.00007 | $0.00162 |
Grade A, and why
foundry-cheatcodes 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 2mo 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.
How it starts
The opening of the file, as written. The whole thing — 178 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Foundry Cheatcodes
vm.* cheatcodes are how Forge tests manipulate EVM state and assert behavior. They live in forge-std/Test.sol (Vm interface). Full reference: https://getfoundry.sh/reference/cheatcodes/overview
When to use this skill
- Writing a test that needs to fake
msg.sender(prank) - Asserting a revert (
expectRevert) - Asserting an event was emitted (
expectEmit) - Mocking an external contract call (
mockCall) - Manipulating block context (
warp,roll,fee) - Setting balances or storage directly (
deal,store,etch) - Forking mainnet for integration tests (
createFork,selectFork) - Reading env vars or JSON in tests/scripts (
envUint,parseJson)
Cheat sheet — most common
Block & time
| Cheat | Use |
|---|---|
vm.warp(uint256) |
Set block.timestamp |
vm.roll(uint256) |
Set block.number |
vm.fee(uint256) |
Set block.basefee |
vm.chainId(uint256) |
Set block.chainid |
vm.prevrandao(bytes32) |
Set block.prevrandao (post-merge) |
vm.txGasPrice(uint256) |
Set tx.gasprice |
Caller / pranks
| Cheat | Use |
|---|---|
vm.prank(addr) |
Next call uses addr as msg.sender |
vm.prank(addr, origin) |
Also set tx.origin |
vm.startPrank(addr) |
All calls until stopPrank |
vm.stopPrank() |
End an active prank |
vm.readCallers() |
Inspect current prank mode |
Account state
| Cheat | Use |
|---|---|
vm.deal(addr, uint256) |
Set ETH balance |
vm.store(addr, slot, value) |
Write a storage slot |
vm.load(addr, slot) |
Read a storage slot |
vm.etch(addr, bytecode) |
Replace bytecode at addr |
vm.setNonce(addr, uint64) / vm.getNonce(addr) |
Nonce control |
Expectations
| Cheat | Use |
|---|---|
vm.expectRevert() |
Next call must revert (any reason) |
vm.expectRevert(bytes selector) |
Must revert w/ that selector (custom errors) |
vm.expectRevert(bytes message) |
Must revert w/ that bytes/string |
vm.expectEmit(true, true, true, true) |
Next emit must match |
vm.expectCall(addr, calldata) |
A specific external call must happen |
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.
- 2mo ago First seen · 178 lines · 70 tokens per session scan A 753cb19c59fd
foundry-cheatcodes is a skill published in the GitHub repository Hirama/solidity-agentic-stack (6 stars, last pushed 4mo ago), licensed MIT. It adds 70 tokens to every session and 1,620 once invoked, about $0.0003 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 2026-08-31.
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