What problem does it solve? It prevents API misuse when building Cloudflare Sandbox applications on the @cloudflare/sandbox@next (1.0 preview) line, where process execution, terminals, and interpreter APIs differ significantly from the stable package. ## Core Features & Use Cases - Package Line Gate: Verifies the npm dependency and container image both match the @next preview line before writing code, and redirects to sandbox-stable or sandbox-migrate-to-next when appropriate. - API Contract Enforcement: Documents non-negotiable behaviors such as argv-based exec returning process handles, no implicit shell, per-launch cwd/env, and no process stdin. - Documentation Retrieval Map: Routes each task (processes, terminals, interpreter, lifecycle, errors, files, mounts, tunnels) to the correct official preview documentation page. - Use Case: When building a Worker that runs Python code in an isolated container, use this Skill to correctly call sandbox.exec with an argv list, collect results via process.output(), and avoid inventing removed stable APIs. ## Quick Start Ask the AI to create a Cloudflare Worker using @cloudflare/sandbox@next that executes a Python command in a sandbox and returns its stdout and exit code.