DOOM MCP vs Fixa

Chris Nager built a fully playable DOOM that runs as an MCP (Model Context Protocol) app, rendering inline inside Claude and ChatGPT without a separate browser tab. The architecture uses two MCP tools — create_doom_session for inline-capable hosts and get_doom_launch_url as a browser fallback — combined with cloudflare/doom-wasm for the game runtime and a signed token system that maintains session state across both surfaces. The result is the same session whether you're playing inline or in a tab. The key technical challenge was avoiding iframe and CSP (Content Security Policy) issues. Rather than embedding a browser page inside the MCP iframe, the DOOM canvas runs directly inside the host's iframe — a subtle but critical distinction that resolved a class of rendering and input-handling bugs. The final implementation is intentionally stripped down: no save/load, no persistence adapters, just stable playable DOOM. Beyond the novelty, this project is a concrete demonstration that MCP apps are interactive surfaces, not just tool-calling JSON endpoints. The progressive enhancement pattern — same signed-token foundation serving both inline and browser modes — is a reusable architecture for any game or interactive experience that wants to live inside an AI assistant. Nager open-sourced the implementation and the blog post is a detailed technical breakdown.

Fixa is a cloud-native AI coding agent that goes beyond code completion to handle end-to-end project scaffolding, deployment, and iterative refinement — all without any local setup. Launched on Product Hunt today, it lets developers describe a project in plain language and returns a running, deployed application within minutes. Unlike Bolt, Replit, or Lovable — which run in browser-based sandboxes — Fixa provisions real cloud infrastructure (compute, database, CDN) on your behalf and maintains persistent agent state between sessions. You can leave a session and return to find the agent has continued iterating on your project based on usage data it collected from real traffic. The differentiator is the feedback loop: Fixa monitors the deployed app's error logs and user interactions and proactively proposes fixes or improvements without being asked. It supports Node.js, Python, and Go projects, connects to GitHub for version control, and integrates with Stripe, Supabase, and Cloudflare out of the box.