feat(build-arena): AI-powered build performance benchmark system

[rjwalters]

Overview

Build Arena is an AI-powered benchmark system that races Elide against traditional Java build tools (Maven/Gradle) using autonomous Claude Code agents. This PR introduces the complete system including frontend, backend, Docker infrastructure, and observability tools.

Demo

https://github.com/user-attachments/assets/your-demo-video-here

What's Included

🏗️ Core Infrastructure

Backend (tools/build-arena/backend/)

• Race API - Start/monitor build races between Elide and standard tools
• WebSocket Servers - Real-time terminal streaming and race status updates
• Job Management - Queue system with SQLite persistence
• Race Minder - Autonomous agent that auto-approves Claude Code prompts
• Container Management - Docker integration for isolated build environments

Frontend (tools/build-arena/frontend/)

• Race Dashboard - Real-time race visualization with live terminal output
• Build Metrics - Charts comparing build times, resource usage
• Repository Form - Submit any Java GitHub repo for benchmarking
• WebSocket Integration - Live updates from both containers

Docker Images (tools/build-arena/docker/)

• elide-builder - Claude Code + Elide + Java 17
• standard-builder - Claude Code + Maven + Gradle + Java 17
• Multi-platform support (linux/amd64, linux/arm64)
• Pre-configured for headless autonomous operation

🤖 Autonomous AI Agents

Race Minder (backend/src/services/race-minder.ts)

Monitors terminal WebSocket and automatically:

• ✅ Approves API key confirmation
• ✅ Approves workspace trust prompts (multiple Claude Code 2.0.30 variations)
• ✅ Auto-approves git clone commands
• ✅ Auto-approves build tool commands (elide, mvn, gradle)
• ✅ Detects completion signals (bell emoji, "BUILD COMPLETE", etc.)
• ✅ Handles API errors with retry logic

Detection Patterns:

// Workspace trust (Claude Code 2.0.30)
"Ready to code here?"                              // Standard
"Is this a project you created or one you trust"  // Elide
"Quick safety check"                               // Fallback

// Completion signals
/🔔/, /BUILD COMPLETE/i, /Build succeeded/i, /Total time:/i

Container Instructions (docker/CLAUDE.md)

Detailed step-by-step instructions for Claude Code:

1. Clone repository
2. Analyze project structure (Maven/Gradle detection)
3. Execute timed build with appropriate tool
4. Run tests to verify build
5. Ring bell (🔔) to signal completion

📊 Observability & Debugging

Terminal Output Dumper (scripts/dump-terminal-output.ts)

cd backend
pnpm exec tsx ../scripts/dump-terminal-output.ts <containerId>

• Connects to container WebSocket in read-only mode
• Captures 10-second snapshot of terminal output
• Shows message counts, output length, current state

Comprehensive Documentation (docs/OBSERVABILITY.md)

• Quick start guide for monitoring races
• Debugging workflows for common issues
• Testing procedures for components
• File reference with line numbers
• Advanced debugging techniques

Backend Log Filtering

Use regex patterns to monitor specific events:

# Monitor all minder activity
Minder:

# Monitor approvals only
Auto-approving:|Bell rung|approved

# Monitor errors
Error|error|API Error

🎨 UI Features

Race View

• Side-by-side terminals - Watch both builds in real-time
• Live status updates - Connection state, approval counts
• Build timer - Duration tracking for each container
• Countdown to auto-start - Visual countdown before race begins
• Completion detection - Automatic finish line detection

Build Metrics

• Performance comparison - Bar charts of build times
• Resource usage - Memory, CPU tracking (planned)
• Success rate - Win/loss statistics per tool
• Historical data - SQLite database persistence

Architecture

┌─────────────┐
│  Frontend   │ (React + Vite)
│   :3000     │
└──────┬──────┘
       │ HTTP + WebSocket
       ▼
┌─────────────┐
│  Backend    │ (Node.js + Express)
│   :3001     │
└──────┬──────┘
       │ Docker API
       ▼
┌─────────────────────────────────┐
│     Docker Containers           │
│  ┌─────────────┐ ┌────────────┐│
│  │elide-builder│ │standard-   ││
│  │             │ │builder     ││
│  │ Claude Code │ │Claude Code ││
│  │ + Elide     │ │+ Maven     ││
│  │ + Java 17   │ │+ Gradle    ││
│  └─────────────┘ └────────────┘│
└─────────────────────────────────┘
       ▲
       │ WebSocket (terminal I/O)
       │
┌──────┴──────┐
│ Race Minder │ (Autonomous approval agent)
└─────────────┘

Key Workflows

Starting a Race

# 1. Start services
cd /Users/rwalters/GitHub/elide/tools/build-arena
pnpm dev

# 2. Submit a repository (API or UI)
curl -X POST http://localhost:3001/api/races/start \
  -H 'Content-Type: application/json' \
  -d '{"repositoryUrl": "https://github.com/google/gson"}'

# 3. Watch in browser
open http://localhost:3000

Monitoring with Observability Tools

# Get race status
curl http://localhost:3001/api/races/status/<jobId>

# Monitor terminal output
cd backend
pnpm exec tsx ../scripts/dump-terminal-output.ts <containerId>

# Check container health
docker ps --filter "name=race-"

Testing

Manual Testing

# Start race via API
curl -X POST http://localhost:3001/api/races/start \
  -H 'Content-Type: application/json' \
  -d '{"repositoryUrl": "https://github.com/google/gson"}'

# Monitor backend logs
tail -f backend/logs/app.log | grep "Minder:"

# Use terminal dumper
cd backend && pnpm exec tsx ../scripts/dump-terminal-output.ts <containerId>

Playwright Tests

cd /Users/rwalters/GitHub/elide/tools/build-arena
pnpm test tests/terminal-test.spec.ts
pnpm test tests/claude-autonomous-test.spec.ts

Project Structure

tools/build-arena/
├── frontend/              # React frontend (Vite)
│   ├── src/
│   │   ├── components/   # Terminal, Metrics, RepositoryForm
│   │   ├── pages/        # HomePage, TerminalTest, RaceView
│   │   └── hooks/        # useWebSocket, useRaceStatus
│   └── package.json
├── backend/              # Node.js backend
│   ├── src/
│   │   ├── routes/       # API endpoints
│   │   ├── services/     # JobManager, RaceMinder, ContainerManager
│   │   ├── websocket/    # TerminalServer, RaceServer
│   │   └── db/           # SQLite schema
│   └── package.json
├── docker/               # Docker images
│   ├── elide-builder.Dockerfile
│   ├── standard-builder.Dockerfile
│   ├── CLAUDE.md         # Instructions for autonomous builds
│   └── build-images.sh
├── scripts/              # Utility scripts
│   └── dump-terminal-output.ts
├── docs/                 # Documentation
│   └── OBSERVABILITY.md
└── tests/                # Playwright tests
    ├── terminal-test.spec.ts
    └── claude-autonomous-test.spec.ts

Environment Setup

Prerequisites

• Node.js 20+
• pnpm
• Docker Desktop
• Anthropic API key

Installation

cd /Users/rwalters/GitHub/elide/tools/build-arena

# Install dependencies
pnpm install

# Set up environment
echo "ANTHROPIC_API_KEY=your-key-here" > backend/.env

# Build Docker images
cd docker && ./build-images.sh

# Initialize database
pnpm --filter @elide/build-arena-backend db:push

# Start services
pnpm dev

Technology Stack

• Frontend: React 18, Vite, xterm.js, Recharts
• Backend: Node.js, Express, SQLite (Drizzle ORM), WebSocket (ws)
• Docker: Multi-platform images, Bash PTY sessions
• AI: Claude Code CLI 2.0.30, Anthropic API
• Testing: Playwright

Known Issues / Roadmap

Known Issues

1. Claude Code premature exit - Sometimes exits after thinking without requesting commands. Investigating API timeout/error handling.
2. Resource cleanup - Orphaned containers if backend crashes during race.

Roadmap

• Minder status API endpoint for real-time state inspection
• WebSocket recorder replay API for complete message history
• Auto-restart Claude Code if it exits prematurely
• Resource usage metrics (CPU, memory, disk I/O)
• Multi-repository batch benchmarking
• Leaderboard for popular repositories
• GitHub Actions integration for CI benchmarking

Security Considerations

• Docker containers are isolated with read-only filesystems where appropriate
• API key stored in environment variables, not committed to repo
• WebSocket connections validated with container ID checks
• Build instructions limit Claude Code to repo cloning and building only

Performance

• Concurrent races: Supports multiple simultaneous races
• Resource limits: Docker containers have memory/CPU limits
• Database: SQLite for lightweight persistence
• WebSocket: Efficient binary protocol for terminal streaming

Related Issues

Addresses #1106 (Nomad integration) by providing infrastructure for autonomous build testing and performance benchmarking.

Draft Status

This PR is marked as draft for initial team review. Specifically looking for feedback on:

1. Architecture - Is the container/minder/WebSocket design sound?
2. Observability - Are the debugging tools sufficient?
3. AI Agent Behavior - Race minder approval patterns and error handling
4. UI/UX - Dashboard layout and real-time updates
5. Documentation - Clarity and completeness

---

Ready for initial review of the complete Build Arena system. The core functionality works end-to-end. Primary focus areas:

• Race minder detection patterns (workspace trust working great!)
• Observability tools for debugging
• Docker image configuration
• Frontend real-time updates

[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	npm/​react-router-dom@​7.9.5
	npm/​@​types/​uuid@​9.0.8
	npm/​@​types/​express@​4.17.25
	npm/​@​xterm/​addon-fit@​0.10.0
	npm/​@​types/​ws@​8.18.1
	npm/​cors@​2.8.5
	npm/​@​types/​react-dom@​18.3.7
	npm/​@​types/​dockerode@​3.3.45
	npm/​@​types/​react@​18.3.26
	npm/​@​types/​node@​20.19.24
	npm/​@​types/​cors@​2.8.19
	npm/​tsx@​4.20.6
	npm/​vite@​5.4.21
	npm/​uuid@​9.0.1
	npm/​node-fetch@​3.3.2
	npm/​autoprefixer@​10.4.21
	npm/​ws@​8.18.3
	npm/​dockerode@​4.0.9
	npm/​tailwindcss@​3.4.18
	npm/​drizzle-orm@​0.44.7
	npm/​@​libsql/​client@​0.15.15
	npm/​swr@​2.3.6
	npm/​@​biomejs/​biome@​1.9.4
	npm/​@​vitejs/​plugin-react@​4.7.0
	npm/​drizzle-kit@​0.31.6
	npm/​@​xterm/​xterm@​5.5.0
	npm/​zod@​3.25.76
	npm/​@​playwright/​test@​1.56.1

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 42.94%. Comparing base (c8c853d) to head (8ec8275).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1755   +/-   ##
=======================================
  Coverage   42.94%   42.94%           
=======================================
  Files         895      895           
  Lines       42415    42415           
  Branches     5959     5959           
=======================================
  Hits        18216    18216           
  Misses      21997    21997           
  Partials     2202     2202           

Flag	Coverage Δ
jvm	42.94% <ø> (ø)
lib	42.94% <ø> (ø)

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