What is ARBuilder CLAUDE.md?

Project instructions for ARBuilder, an AI development assistant for the Arbitrum blockchain ecosystem. Arbitrum is a network for running Ethereum-compatible applications with lower costs.

Use it when developing ARBuilder or its tools for Rust-based Stylus smart contracts, TypeScript SDK connections, cross-chain messaging, full-stack applications, or Orbit chains.

It gives a coding agent the project’s purpose, layout, development commands, and setup details so it can work in the repository with the right context.

How Quantum3-Labs/ARBuilder configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to Quantum3-Labs/ARBuilder. 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/Quantum3-Labs/ARBuilder/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/Quantum3-Labs/ARBuilder

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/quantum3-labs/arbuilder/claude-md/github.svg)](https://agentmods.dev/instructions/quantum3-labs/arbuilder/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/quantum3-labs/arbuilder/claude-md"><img src="https://agentmods.dev/badge/instructions/quantum3-labs/arbuilder/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/quantum3-labs/arbuilder/claude-md"><img src="https://agentmods.dev/badge/instructions/quantum3-labs/arbuilder/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 5,543 This file is loaded in full into every session.

When invoked 5,543 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	$0.05543	$0.05543
Opus 5.5	$0.02217	$0.02217
Sonnet 5.5	$0.01109	$0.01109
Haiku 4.5	$0.00554	$0.00554

Measured 2mo ago against content hash bf0d72537b00, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ARBuilder 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 · 479 lines

How it starts

The opening of the file, as written. The whole thing — 479 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

ARBuilder is an AI-powered development assistant for the Arbitrum ecosystem. It uses RAG (Retrieval-Augmented Generation) to provide context-aware code generation for:

Stylus smart contracts (Rust/WASM)
Arbitrum SDK bridging (TypeScript)
Cross-chain messaging (L1 ↔ L2 ↔ L3)
Full-stack dApps (contracts + backend + frontend + indexer)
Orbit chain deployment (@arbitrum/orbit-sdk)

Repository Structure

ArbBuilder/
├── src/
│   ├── mcp/                  # MCP server for IDE integration
│   │   ├── server.py         # Main MCP server
│   │   ├── tools/            # 19 MCP tools (M1: 6, M2: 3, M3: 5, M4: 5)
│   │   ├── resources/        # Static knowledge (11 resources)
│   │   └── prompts/          # Workflow templates
│   ├── embeddings/           # Vector DB and retrieval
│   │   ├── vectordb.py       # ChromaDB wrapper with hybrid BM25+vector search
│   │   └── reranker.py       # BM25 + LLM reranking
│   ├── templates/            # Code generation templates
│   │   ├── stylus_templates.py   # M1: Stylus contracts
│   │   ├── backend_templates.py  # M3: NestJS/Express (ABI placeholder support)
│   │   ├── frontend_templates.py # M3: Next.js + wagmi (ABI placeholder support)
│   │   ├── indexer_templates.py  # M3: The Graph subgraphs
│   │   ├── oracle_templates.py   # M3: Chainlink integrations
│   │   └── orbit_templates.py    # M4: Orbit chain deployment (@arbitrum/orbit-sdk)
│   ├── utils/                # Shared utilities
│   │   ├── version_manager.py    # SDK version management
│   │   ├── env_config.py         # Centralized env var configuration
│   │   ├── abi_extractor.py      # Stylus ABI extraction from Rust code
│   │   └── compiler_verifier.py  # Docker-based cargo check verification
│   └── preprocessing/        # Text chunking and cleaning
├── scraper/                  # Data collection (web + GitHub)
├── data/
│   ├── raw/                  # Scraped docs and repos
│   ├── processed/            # Pre-processed chunks
│   └── chroma_db/            # Vector database (local)
├── tests/                    # Test suites
├── docs/                     # Documentation
└── scripts/                  # Utility scripts

Read the full file on GitHub · 479 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 · 479 lines · 5,543 tokens per session scan A bf0d72537b00

Subscribe to this mod's changes

ARBuilder CLAUDE.md is an instructions file published in the GitHub repository Quantum3-Labs/ARBuilder (24 stars, last pushed 6mo ago), licensed MIT. It adds 5,543 tokens to every session, about $0.0222 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.

Building agents Web3 and blockchain ai-code-generation arbitrium claude cursor developer-tools mcp

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ARBuilder: Instructions file for Claude Code