ryoha000

Cost-aware Cloudflare implementation and review guidance for Workers, D1, R2, KV, Pages, Wrangler, and edge-hosted APIs. Use when Codex designs, edits, reviews, debugs, or deploys Cloudflare-related code or config, especially `wrangler.toml`, Worker entrypoints, storage bindings, upload flows, caching, or infrastructure choices where staying inside free-tier or low-cost limits matters.

Implement a Rust program that saves files to disk and tests the file saving functionality.