Sandbox Agent solves the problem of running AI coding agents in isolated, secure environments while providing a universal HTTP API for control. It runs as a server inside the sandbox and exposes endpoints for streaming events, handling permissions, and managing agent sessions. The tool supports multiple coding agents (Claude Code, Codex, OpenCode, Cursor, Amp, Pi) and abstracts their different proprietary APIs into a single interface, allowing developers to swap agents via configuration changes rather than rewriting integrations.