solidity

A set of coding guidelines for Solidity, the programming language used to write blockchain smart contracts, with Foundry, a toolkit for building and testing them.

In plain words
What is it for?
Writing and reviewing Solidity smart contracts in Foundry projects, including interfaces, structs, enums, mappings, custom types, and naming conventions.
Why use it?
It gives consistent advice for organizing contract data, naming code, and using Solidity's type system, reducing avoidable mistakes and unclear code.

Cursor rule

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 rules/chand1012/cursorrules/solidity
Clone the repo
git clone --depth 1 https://github.com/chand1012/cursorrules
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 1,124 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 $0.00000 $0.01124
Opus 5 $0.00000 $0.00562
Sonnet 5 $0.00000 $0.00225
Haiku 4.5 $0.00000 $0.00112

Measured yesterday against content hash c8ff79939d9e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

solidity 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 yesterday.

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.

languages/solidity.mdc · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Solidity Foundry Development Best Practices

This document provides guidelines for writing smart contracts in Solidity using the Foundry framework. It adapts concepts from TypeScript best practices to suit Solidity's unique type system, execution environment, and Foundry's tooling.

Type System

  • Use interfaces to define function signatures for external contract interactions (e.g., ERC20 interfaces).
  • Prefer structs to group related data into a single unit (e.g., struct User { address addr; uint256 balance; }).
  • Use enums to represent discrete states or options (e.g., enum Status { Pending, Active, Closed }).
  • Leverage mappings for efficient key-value storage (e.g., mapping(address => uint256) balances).
  • Use custom types (Solidity 0.8.8+) for clarity and type safety (e.g., type UserId is uint256;).

Naming Conventions

  • Use PascalCase for contract, struct, enum, and interface names (e.g., MyContract, UserStruct).
  • Use camelCase for function and variable names (e.g., transferFunds, userBalance).
  • Use UPPER_CASE for constants (e.g., MAX_SUPPLY, FEE_PERCENT).
  • Use descriptive names with auxiliary verbs where applicable (e.g., isPaused, hasRole).
  • Prefix events with Log for clarity (e.g., event LogTransfer(address from, address to, uint256 amount)).

Code Organization

  • Follow Foundry's default project structure:
    • src/ for smart contracts.
    • test/ for test files (use .t.sol suffix for test contracts).
    • script/ for deployment and interaction scripts written in Solidity.
    • lib/ for external dependencies (managed as git submodules).
  • Keep related contracts in the same file or directory for logical grouping.
  • Use libraries for reusable code (e.g., math operations, string utilities).
  • Organize imports at the top of the file, grouped by source (e.g., local files, OpenZeppelin contracts).
  • Include an SPDX license identifier at the top of each file (e.g., // SPDX-License-Identifier: MIT).

Read the full file on GitHub · 72 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. yesterday First seen · 72 lines · 1,124 tokens per session scan A c8ff79939d9e

Subscribe to this mod's changes

solidity is a cursor rule published in the GitHub repository chand1012/cursorrules (13 stars, last pushed 9mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,124 tokens. 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.