01-hello-sandbox

Hello Sandbox

Minimal Sandcaster example — a single agent in an E2B sandbox.

Prerequisites

• sandcaster CLI installed (from monorepo: cd apps/cli && bun link)

Setup

export E2B_API_KEY="your-key"       # https://e2b.dev/dashboard
export OPENAI_API_KEY="your-key"    # https://platform.openai.com/api-keys

Run

sandcaster "Hello, what can you do?"

What Happens

The agent starts in a fresh E2B sandbox, responds to your prompt, and tears down the sandbox when done. This is the simplest possible Sandcaster configuration.

Configuration

See sandcaster.json for the full configuration. Key settings:

• model: gpt5 (OpenAI gpt-5.4 — cost-efficient default)
• systemPrompt: basic assistant persona

Troubleshooting

• "No LLM provider API key found": Set OPENAI_API_KEY in your environment
• "E2B_API_KEY not set": Get a key at https://e2b.dev/dashboard
• Model not available: Replace gpt5 with sonnet or haiku in sandcaster.json