Show HN: Write one primary AI config file; Export it to all AI Coding Assistants (apps.apple.com)

Agent Smith is a lightweight tool (Show HN) that lets developers author a single "Master Instruction" file for a project and export it into assistant-specific instruction files (AGENTS.md, CLAUDE.md, GEMINI.md) so Gemini, Claude and Codex-based coding assistants can all read the same guidance. It provides a smart template with built-in sections for project overview, coding standards, style guidelines and customizable context, saves exports directly to the project root, and offers one-click export to generate identical assistant files. The app is published by Phantom Particle and the developer indicates the app does not collect data. For AI/ML engineers and teams that use multiple coding assistants, Agent Smith reduces prompt drift and maintenance overhead by standardizing prompts and environment context across tools, improving reproducibility, onboarding and consistent code style enforcement. Technically, it doesn’t wrap or proxy the assistants; it produces plain instruction files tailored per agent and places them in the repo for discovery (so integration with editors, CI checks or shared repos is straightforward). Practical caveats remain: assistant-specific quirks and token/context limits may still require fine-tuning, and care is needed to avoid embedding secrets in repo-visible prompts even if the app itself claims no data collection.