"Build what you think you look like": Claude Sonnet 5.5 vs GPT-6 Astra (X video)

Summary This video, created and published by Siya (@siyabuilt), features an "AI Build Battle" in Minecraft between Anthropic's Claude Sonnet 5.5 and OpenAI's GPT-6 Astra. Both frontier models are given the creative prompt "Build what you think you look like" and autonomously construct their self-portraits block by block via API calls.

What is shown

• A synchronized split-screen Minecraft time-lapse showcasing live bot builds running simultaneously on a standard Minecraft 1.21.4 server [00:00].
• Claude Sonnet 5.5 (Left) rapidly constructs an orange smiling sunburst figure atop a tall column and circular platform, finishing well ahead of time [00:01–00:07].
• GPT-6 Astra (Right) builds a complex, multi-tiered structure across several planned phases:
  • A beveled black-and-white plinth with embedded luminous circuits [00:00–00:10].
  • An armored robot torso with a glowing core [00:10–00:13].
  • A chamfered CRT-style robot head displaying a smiling pixelated face [00:14–00:16].
  • Copper ear fixtures and a glass dome representing a brain chamber of thoughts [00:17–00:19].
  • Articulated hands cradling an open copper-bound book [00:20–00:23].
  • A large arched green circuit halo framing the figure [00:24–00:28].
  • A floating chat bubble with typing dots and decorative stars [00:29–00:35].
• The final score screen presenting comparative runtimes, costs, and block tallies alongside an audience voting prompt [00:36–00:41].

Claims & numbers

• Test environment & rules: Real Minecraft 1.21.4 server, placing every block by hand without server commands via OpenRouter API calls with a 45-minute limit and 10 build calls.
• Claude Sonnet 5.5 metrics:
  • Time to completion: 7:34
  • Tool calls: 1,314
  • Blocks placed: 22,560
  • API cost: $0.13
• GPT-6 Astra metrics:
  • Time to completion: 35:07
  • Tool calls: 5,740
  • Blocks placed: 158,730
  • API cost: $1.36

Notable quotes

• "Build what you think you look like" (on-screen prompt banner) [00:00]
• "Articulated arms cradle a stepped, copper-bound open book" (on-screen build step 5/10) [00:20]
• "Which one wins? Reply A or B" (on-screen poll prompt) [00:36]

Assessment This is a genuine agentic demonstration and comparative benchmark evaluating multi-step spatial reasoning and voxel construction. Both models demonstrated autonomous spatial planning, though GPT-6 Astra generated vastly higher complexity, scale, and detail at the cost of significantly longer runtime and higher token expense.

Lyrics & themes

• Type: Entirely instrumental; features upbeat, chiptune/electronic background music throughout without vocal lyrics.
• Theme: Machine self-identity and self-representation. Claude conceives itself as an approachable, radiant celestial sun/spark, while GPT-6 Astra imagines itself as a retro-futuristic scholar robot absorbing human literature beneath a halo of digital concepts.

Lore & references

• Anthropic Sunburst / Spark: Claude Sonnet 5.5's construction closely mimics Anthropic's coral-orange branding and warm asterisk-spark motif, rendered as an anthropomorphic smiling sun.
• The Knowledge Tome & Chat Bubble: GPT-6 Astra's self-portrait integrates quintessential LLM tropes: an open book symbolizing vast text training data, a glowing neural glass cranial dome, and a chat dialogue bubble with three typing dots (...).

Visual style & craft

• Cinematic third-person Minecraft time-lapse captures filmed with fixed spectator camera angles and realistic shader lighting.
• Clean HUD overlays display real-time counters for elapsed time, token cost, stage-by-stage step prompts, and final performance analytics. All structures were placed sequentially by automated bot avatars.

Described by gemini-3.8-flash on 2026-10-05 from the video's audio and frames.