What is collectible-casts CLAUDE.md?

Development instructions for Collectible Casts, a Foundry project that creates Ethereum smart contracts in Solidity.

Use them when changing contracts, specifications, task plans, or tests, especially when you need targeted tests or gas reports.

They document the project plans and the commands for compiling contracts, running tests, checking contract sizes, and measuring gas use.

How farcasterxyz/collectible-casts configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to farcasterxyz/collectible-casts. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/farcasterxyz/collectible-casts/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/farcasterxyz/collectible-casts

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/farcasterxyz/collectible-casts/claude-md/github.svg)](https://agentmods.dev/instructions/farcasterxyz/collectible-casts/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/farcasterxyz/collectible-casts/claude-md"><img src="https://agentmods.dev/badge/instructions/farcasterxyz/collectible-casts/claude-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/farcasterxyz/collectible-casts/claude-md"><img src="https://agentmods.dev/badge/instructions/farcasterxyz/collectible-casts/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 3,579 This file is loaded in full into every session.

When invoked 3,579 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.03579	$0.03579
Opus 5.5	$0.01432	$0.01432
Sonnet 5.5	$0.00716	$0.00716
Haiku 4.5	$0.00358	$0.00358

Measured 2mo ago against content hash 99a75fdf1123, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

collectible-casts CLAUDE.md 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.

CLAUDE.md · 445 lines

How it starts

The opening of the file, as written. The whole thing — 445 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

This is a Foundry-based Ethereum smart contract development project. Foundry is a Rust-based toolkit that provides a complete development environment for Solidity smart contracts.

Foundry Documentation: https://getfoundry.sh/

Project Documentation

SPEC.md - Complete specification for the Collectible Casts system, including architecture, goals, and detailed contract requirements
PLAN.md - High-level implementation plan outlining development phases and testing strategy
TASKS.md - Detailed task breakdown with specific implementation steps and test scenarios

Essential Commands

Building and Testing

forge build              # Compile all contracts
forge build --sizes      # Compile and show contract sizes
forge test              # Run all tests
forge test -vvv         # Run tests with maximum verbosity (useful for debugging)
forge test --match-test testName  # Run specific test
forge test --match-contract ContractName  # Run tests for specific contract
forge test --gas-report  # Run tests with gas usage report

# Fuzz testing profiles
forge test                    # Default: 2048 fuzz runs
FOUNDRY_PROFILE=ci forge test # CI: 10,000 fuzz runs
FOUNDRY_PROFILE=deep forge test # Deep: 50,000 fuzz runs
forge test --fuzz-runs 100000 --fuzz-seed 0x123  # Custom deterministic deep fuzzing

Code Quality

forge fmt               # Format all Solidity files (120 char line length)
forge fmt --check       # Check formatting without modifying files
forge snapshot          # Generate gas usage snapshots
forge snapshot --check  # Compare gas usage against .gas-snapshot
forge coverage          # Generate test coverage report (minimum 94%)
python3 script/check-coverage.py  # Verify 100% coverage for production contracts

Local Development

anvil                   # Start local Ethereum node for testing
anvil --fork-url <RPC_URL>  # Fork mainnet for testing

Read the full file on GitHub · 445 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.

2mo ago First seen · 445 lines · 3,579 tokens per session scan A 99a75fdf1123

Subscribe to this mod's changes

collectible-casts CLAUDE.md is an instructions file published in the GitHub repository farcasterxyz/collectible-casts (25 stars, last pushed today), licensed MIT. It adds 3,579 tokens to every session, about $0.0143 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 2026-08-30.

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collectible-casts CLAUDE.md next to 6 instructions from other repositories
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collectible-casts: Instructions file for Claude Code