AI tool comparison
DOOM MCP vs Gemini CLI
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Developer Tools
DOOM MCP
Play DOOM inline inside Claude or ChatGPT — full game, no browser needed
75%
Panel ship
—
Community
Free
Entry
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.
Developer Tools
Gemini CLI
Google's free, open-source terminal AI agent with 1M context window
75%
Panel ship
—
Community
Free
Entry
Gemini CLI is Google's open-source terminal AI coding agent, built on Gemini 2.5 Pro with a 1-million-token context window — the largest of any terminal agent on the market. It implements a ReAct loop with native MCP support, Google Search grounding for up-to-date information, and a GEMINI.md config file system similar to Claude Code's CLAUDE.md. Apache 2.0 licensed. The free tier is unusually generous: Google account holders get full access with no per-token charges, subsidized by Google's strategic interest in developer adoption. The 1M context window is the key differentiator — it allows Gemini CLI to read an entire large codebase in one pass, something Claude Code and Codex CLI both truncate. Benchmarks show it leads on UI/CSS tasks and large-codebase navigation, while lagging on complex multi-file refactors. At 99,000 GitHub stars, Gemini CLI is the third-most-starred coding agent after Claude Code and Claw Code. The combination of free pricing, open source, and 1M context has driven rapid adoption among developers who hit token limits on other tools.
Reviewer scorecard
“The signed-token progressive enhancement pattern is the part worth stealing. This is a clean reference architecture for MCP interactive apps, and DOOM just happens to be the demo case.”
“1M context and free is a combination no other terminal agent matches. I use it specifically for legacy codebase archaeology — when I need to understand a 200k-line repo before I touch it, Gemini CLI is the only tool that can hold the whole thing in memory. For greenfield projects I still reach for Claude Code.”
“Fun proof of concept but let's be honest: if your AI assistant is hosting a DOOM session, something has gone wrong with your productivity. The MCP-as-interactive-surface insight is real, but this specific app has no utility.”
“Free always comes with strings. Google has a long history of abandoning developer tools — Stadia, Duo, Cloud Run free tiers all got axed or repriced. The 1M context is impressive but the output quality on complex reasoning tasks still trails Anthropic and OpenAI. Wait for the pricing to stabilize before depending on it.”
“Every major compute platform's pivot point is when it runs DOOM. MCP running DOOM means MCP is a real platform now. The implications for interactive AI-embedded experiences are significant.”
“Google making terminal AI agents free is an aggressive move to commoditize the layer above the model. If Gemini CLI reaches 10M developer installs, Google has a direct relationship with the world's most influential users. This is infrastructure play, not a product play — and it will succeed on those terms.”
“As someone who thinks about interactive experiences, the idea of game-like UI living inside an AI context is genuinely exciting. This is a crude ancestor of what interactive AI-native media could become.”
“The Google Search grounding is the feature I didn't know I needed. When I'm building with APIs that changed last month, Gemini CLI actually knows about it. Claude Code is still guessing from training data. For staying current on fast-moving frameworks, this wins.”
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