ARBuilder — Final Report
Project: ARBuilder — AI-Powered Development Assistant for the Arbitrum Ecosystem
Team: Quantum3 Labs
Grant Program: Arbitrum Foundation Developer Tooling
Period: January – March 2026
Milestones Completed: 5/5
| Link | URL |
|---|---|
| GitHub Repository | GitHub - Quantum3-Labs/ARBuilder: AI-powered code generator for Arbitrum Stylus, SDK bridging, dApps & Orbit chains — 19 MCP tools with RAG · GitHub |
| Hosted Service | https://arbuilder.app |
| YouTube Channel | https://www.youtube.com/@Arbuilder-app |
| Glama MCP Listing | ARBuilder by Quantum3-Labs | Glama |
| Tutorial Video | https://youtu.be/T0bGSYwjMeo |
1. Overview
ARBuilder is an open-source MCP (Model Context Protocol) server that provides AI-powered code generation for the Arbitrum ecosystem. It transforms natural language prompts into production-ready code for:
- Stylus smart contracts (Rust/WASM) — SDK 0.10.0
- Cross-chain bridging (ETH/ERC20 across L1, L2, L3)
- Full-stack dApps (NestJS + Next.js + The Graph + Chainlink)
- Orbit chain deployment (config, rollup, validators, node setup)
The tool uses a RAG (Retrieval-Augmented Generation) pipeline with hybrid BM25 + vector search over 40+ curated Arbitrum repositories, ensuring generated code follows current SDK patterns rather than relying on outdated LLM training data.
19 MCP tools work inside Cursor, VS Code, and Claude Desktop — or via the hosted playground at arbuilder.app.
2. Deliverables & Milestone Completion
All 5 milestones have been completed and merged to the main branch.
| # | Milestone | Description | Status | PRs |
|---|---|---|---|---|
| M1 | Proposal + PoC Improvement | Updated proposal, improved PoC, documentation | Complete | — |
| M2 | Stylus + SDK RAG | Stylus code generation (6 tools), Arbitrum SDK bridging (3 tools), MCP integration, tutorial video | Complete | #4, #5, #6, #7 |
| M3 | Full dApp Builder | Backend, frontend, indexer, oracle, orchestration (5 tools), hybrid RAG, ABI extraction | Complete | #9, #10, #11, #12, #13 |
| M4 | Orbit Integration | Chain config, rollup deployment, validator setup, Q&A, orchestration (5 tools) | Complete | #14 |
| M5 | Final Report + Metrics | ARBuilder v1.0, final report, KPIs | Complete | #15, #16, #17, #19 |
Key Technical Deliverables
| Component | Details |
|---|---|
| MCP Tools | 19 tools across 4 modules (M1: 6, M2: 3, M3: 5, M4: 5) |
| Templates | 7 Stylus contract templates + 9 Orbit deployment templates |
| RAG Pipeline | Hybrid BM25 + vector search (BGE-M3, 1024 dimensions) + cross-encoder reranking |
| Code Validation | Docker-based cargo check with up to 3 auto-fix attempts, 6-phase fix architecture |
| Hosted Service | Cloudflare Workers (Workers AI, Vectorize, D1, KV, Queue) |
| Test Suite | 451 unit/integration tests including TypeScript compilation and bash syntax validation |
| Ingestion Pipeline | Worker-native cron (every 6 hours) — scrape, chunk, embed, upsert |
3. Developer Adoption & Usage Metrics
3.1 Platform Usage
Data source: Cloudflare D1 usage_logs (MCP endpoint)
| Metric | Value |
|---|---|
| Total code generation requests | 1,921 |
| Total LLM tokens consumed | 5,340,565 |
| Overall success rate | 99.7% (1,915/1,921) |
| Average latency | 15.6 seconds |
| Peak daily usage | 333 requests (March 5, 2026) |
| Active tracking period | Feb 24 – Mar 8, 2026 |
3.2 Requests by Tool
| Tool | Requests | Category |
|---|---|---|
| generate_stylus_code | 488 | M1: Stylus |
| generate_bridge_code | 327 | M2: SDK |
| generate_messaging_code | 183 | M2: SDK |
| ask_bridging | 183 | M2: SDK |
| orchestrate_dapp | 94 | M3: dApp |
| generate_indexer | 84 | M3: dApp |
| generate_tests | 69 | M1: Stylus |
| ask_stylus | 68 | M1: Stylus |
| generate_frontend | 60 | M3: dApp |
| generate_backend | 57 | M3: dApp |
| get_workflow | 51 | M1: Stylus |
| ask_orbit | 44 | M4: Orbit |
| generate_orbit_deployment | 42 | M4: Orbit |
| get_stylus_context | 38 | M1: Stylus |
| generate_oracle | 35 | M3: dApp |
| generate_validator_setup | 33 | M4: Orbit |
| generate_orbit_config | 33 | M4: Orbit |
| orchestrate_orbit | 32 | M4: Orbit |
3.3 Developer Reach
| Channel | Details |
|---|---|
| Registered users (arbuilder.app) | 5 accounts with API keys |
| External developers with mainnet deployments | 5 unique developers |
| GitHub maintainers | 4 (wms2537, DiegoFloresWenHao, macoloye, ngjupeng) |
| GitHub stars | 21 |
| YouTube videos | 3 tutorials published |
| Glama quality score | AAA (highest tier) |
4. Mainnet Deployments — Case Studies
Five projects built with ARBuilder have been independently deployed to Arbitrum One mainnet by external developers:
| # | Project | Developer | Contract Address | Description |
|---|---|---|---|---|
| 1 | Arbitrum TipJar | jaysun15 | 0xba39c706dc01a10c974d5dc355e0725def232e2e |
On-chain tipping |
| 2 | ArbiDrop | Jalaa532 | 0x27ccb5c8da8ae0e2c8b349a0a7d14627429c9569 |
Token airdrop distribution |
| 3 | ArbTokenLaunch | benedicther | 0x1Da2ce71c789E43775c374920b345998B1F72abC |
Token launch platform |
| 4 | Credential Revocation Registry | ajeelll | 0x5c31858bd9769cfc29dc36f0cb40bc90cdff321a |
Verifiable credential registry |
| 5 | DisasterReliefLedger | samdasak | 0xff5a49998772f123c26333fa3a033bdb9cd1fdc7 |
Disaster relief fund tracking |
Testnet projects (Arbitrum Sepolia):
- test-erc20-stylus — ERC20 token on Stylus SDK 0.10.0
- arcadedao-orbit — Orbit chain deployment
- prediction-market-dapp — Full-stack prediction market
5. KPI Achievement
| KPI | Target | Achieved | Evidence |
|---|---|---|---|
| Unique developers | ≥10 | 12 | Registered users + GitHub contributors + mainnet deployers (deduplicated) |
| Code generation requests | ≥100 | 1,921 (19.2x target) | Cloudflare D1 usage_logs — tracked Feb 24 – Mar 8, 2026 (schema) |
| GitHub stars | ≥20 | 21 | GitHub |
| Community contributions | ≥5 | 8 issues, 18 merged PRs | Issues / PRs |
| Case studies | ≥3 | 5 | See Section 4 — all with on-chain contract addresses |
| Projects deployed to mainnet | ≥5 | 5 | See Section 4 — verified on Arbitrum One |
6. Community Engagement & Distribution
6.1 Open Source
| Item | Details |
|---|---|
| License | MIT |
| README | Comprehensive with architecture, quick start, 19-tool reference |
| CONTRIBUTING.md | Development guide, code style, PR process |
| Issue templates | Bug report + feature request |
| Good first issues | 7 open issues labeled for new contributors |
6.2 Directory Listings
| Platform | Status |
|---|---|
| Glama | Listed — AAA score |
| awesome-mcp-servers | Listed |
| awesome-stylus | PR #26 submitted |
| mcp.so | Issue #788 submitted |
6.3 Content & Tutorials
| Content | Link |
|---|---|
| Setup & usage walkthrough | YouTube |
| Prediction market dApp demo | YouTube |
| L3 Orbit chain demo | YouTube |
6.4 Website & SEO
arbuilder.app includes:
- Landing page with all 4 milestone feature sections
- Interactive playground with all 19 tools
- Transparency page (data sources, pipeline status)
- SEO: JSON-LD structured data, Open Graph, Twitter cards, robots.txt, sitemap.xml
- LLM discovery endpoint (/llms.txt) for AI search engines
7. Technical Architecture
RAG Pipeline
Query → BM25 + Vector Search (BGE-M3) → RRF Fusion → Cross-Encoder Reranking → LLM Generation
- Hybrid search over 40+ curated Arbitrum repos and docs
- Cross-encoder reranking for precision
- 65 Stylus compilation rules in system prompts
- Compile verification via Docker
cargo checkwith 3 auto-fix attempts
Code Quality Pipeline
6-phase fix architecture (Python + TypeScript, kept in sync):
- Structural corrections (attributes, extern crate)
- Import resolution (alloc, alloy_sol_types)
- Storage accessor patterns (getter/setter)
- API migration (SDK 0.9.x → 0.10.0)
- Type corrections (B256, U256, as_u64)
- Output sanitization (garbled LLM output)
Deployment
| Mode | Stack |
|---|---|
| Self-hosted | Python MCP server via stdio → Cursor / VS Code / Claude Desktop |
| Hosted | Cloudflare Workers, Workers AI, Vectorize, D1, KV, Queue |
8. Key Learnings
- RAG outperforms fine-tuning for fast-moving SDKs. Stylus SDK went from 0.6 → 0.10.0 in months. RAG allows knowledge base updates in hours, not weeks of retraining.
- Compile verification is non-negotiable. The
cargo check+ auto-fix loop catches errors that static analysis cannot, especially Stylus-specific patterns likeself.vm()migration. - Hybrid search matters. BM25 alone misses semantic similarity; vector search alone misses exact API signatures. The combination with cross-encoder reranking significantly improves code quality.
- Template + LLM hybrid works best. Templates provide reliable scaffolding (100% success rate); LLM fills in custom logic. This gives consistency for common patterns while maintaining flexibility.
- Testing catches real bugs. Our TypeScript compilation tests caught a template substitution ordering bug where
CHAIN_ID_PLACEHOLDERwas being replaced beforePARENT_CHAIN_ID_PLACEHOLDER, corrupting parent chain IDs in generated code.
9. Repository Statistics
| Metric | Value |
|---|---|
| Total commits | 218 |
| Lines of code (Python + TypeScript) | 56,700+ |
| Test cases | 451 |
| Pull requests merged | 18 |
| Issues created | 8 (7 open “good first issue”) |
| Data sources in knowledge base | 40+ |
10. Future Plans
- Continue maintaining the knowledge base as Stylus SDK evolves
- Respond to community issues and contributions via the 7 open “good first issue” items
- Monitor and update directory listings (awesome-mcp-servers, awesome-stylus, mcp.so)
- Explore additional Arbitrum ecosystem integrations based on community feedback
- Track mainnet deployments from new users
ARBuilder is open-source under the MIT license. Built by Quantum3 Labs for the Arbitrum ecosystem.