Claude Opus 5.5 to jakiś kosmos

Summary
In this video, creator tef tests Anthropic’s Claude Opus 5.5 using the Claude Code CLI tool connected to Unreal Engine 5.8 via an Model Context Protocol (unreal-mcp) server. He evaluates the model’s ability to autonomously generate two playable games from scratch using text prompts and image references: an open-world third-person samurai game and a voxel-based Minecraft clone.

What is shown

• [00:00] Launching Claude Code v2.1.280 using Opus 5.5 with xhigh effort on a project titled Vagabond.
• [00:26] Providing reference images and a detailed prompt to create a scenic third-person samurai exploration demo with wind-blown tall grass and sunset lighting.
• [00:41] On-screen comparison displaying token costs ($4 input / $20 output per million tokens for Opus 5.5 vs. $10 / $50 for Fable 5.1) and benchmark comparisons against Fable 5, Opus 4.8, and GPT-5.6 Sol.
• [01:01] Claude Code completing the samurai demo in 1 hour, 31 minutes, and 55 seconds.
• [01:16] Gameplay testing of the generated samurai environment, running across hills of procedural grass toward torii gates and scenic trees.
• [03:08] Prompts Claude Code to add wild wandering wolves, basic sword combos, attack animations, and hit detection.
• [04:06] Demonstrating the newly added sword slash mechanics with light trails and combat with a spawned wolf enemy.
• [05:46] Prompting Claude Code to generate a voxel sandbox Minecraft clone with procedural terrain, dynamic lighting, shaders, and block placement/destruction.
• [06:58] Demonstrating gameplay of the generated voxel demo, showcasing first-person movement, block mining, placing dirt blocks, dynamic water, god rays, and swaying foliage.

Claims & numbers

• Pricing: An on-screen graphic states Opus 5.5 costs $4 input and $20 output per million tokens, compared to Fable 5.1 at $10 input and $50 output (costing 60% less per token).
• Samurai game run cost & time: The presenter reports the samurai demo completed in 1 hour, 31 minutes, and 55 seconds, costing approximately $10 in API credits (claiming Claude Fable 5.1 would have cost nearly $200). Adding wolves and combat took about 25 minutes.
• Minecraft clone run cost & time: The presenter claims the Minecraft demo took approximately 1.5 to 2 hours and consumed $20 of usage credits.
• Comparisons: The presenter claims Opus 5.5 performed better on these game development tasks than Claude Fable 5.1 and GPT-6 Astra.

Notable quotes

• [01:11] "Claude Fable 5.1 would have used nearly 200."
• [01:54] "He did this with only $10. Like, this is actually madness."
• [08:12] "I think without a doubt we can say that Opus 5.5, from what I've tested so far, is the best budget AI."

Assessment
This is a genuine hands-on review and community demo demonstrating autonomous game development with Claude Code and an Unreal Engine MCP server. The generation times are condensed through jump cuts, but the resulting interactive playable builds within Unreal Engine 5.8 are authentic and directly demonstrated on screen.

Described by gemini-3.8-flash on 2026-09-29 from the video's audio and frames.