DOOM MCP vs Rocky

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.

Rocky is a Rust-based SQL transformation engine that brings software engineering discipline to data pipelines. Where tools like dbt gave data teams a version-controlled workflow, Rocky goes further: type-safe compile-time SQL, column-level lineage visualization, git-style branches for isolated testing, and a built-in AI intent layer that stores your purpose as metadata alongside the code. The branching feature is the standout — you can create a branch, run it against an isolated schema, inspect the results, then drop or promote. The column-level lineage shows the full downstream blast radius before you ship a change, tracing any single column back through every aggregation and join to its source. This is the kind of visibility that prevents the "who broke the revenue dashboard" post-mortems that happen in every data team. The AI intent layer is genuinely novel: it stores what a model is supposed to do as metadata, so AI can later explain models, auto-update them when upstream schemas change, and generate tests based on the original intent. Rocky integrates with Dagster via an official plugin and supports DuckDB for local development with no credentials required. With Hacker News coverage and a Rust-native architecture, it's positioned as the data pipeline tool for engineering-forward teams who are tired of YAML-based transformations.