Real head-to-head · same prompt, one shot
Claude Opus 5 vs Fugu Ultra 1.1
The new Anthropic flagship — benched on all 45 one-shot builds the day it landed. vs Sakana's multi-agent orchestrator, v1.1 — routes experts per request.
Head-to-head verdict: Claude Opus 5 wins 18–4 with 1 tie.
What I tested — same prompt, two models
I run the same fixed prompt set through every new model the day it drops — same string, one shot, single HTML file out — and I score the result 0–10 on whether it ran, how close it hit the brief, and how good it looked. Below is what came out when I gave the exact same prompts to Claude Opus 5 and Fugu Ultra 1.1, side by side, on 24 shared tasks inside the Agent Operating System.
Both models were given identical prompts inside the Agent Operating System — no help, no iteration, no "best of N" tricks. I run each prompt once, save the HTML file the model produces, and score it 0–10 on whether it ran, how close it hit the brief, and how good it looked. The scoring is mine. The verdicts below are pulled from my source comparison guides at agentos.guide where I publish every score and the reasoning behind it.
Claude Opus 5 · Benched on all 45 GoldieBench tasks via API on release day, incremental deploys as scores landed.
Fugu Ultra 1.1 · Benched on GoldieBench via Sakana's Responses API (fugu-ultra-v1.1, xhigh reasoning). Game tasks use the skill-infused threejs-game-director prompt plus a controls+graphics fix loop with an anti-regression clamp, judged on a real mid-play frame by the same Opus judge as the field.
Side-by-side on 50 shared tasks
Click any cell to play that model's actual one-shot attempt. Medals are derived from my 0–10 scores per task (highest = 🥇, second = 🥈, third = 🥉).
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Claude Opus 5
Fugu Ultra 1.1
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Where Claude Opus 5 beat Fugu Ultra 1.1
The tasks where I gave Claude Opus 5 a higher 0–10 score on the same prompt — with the actual commentary from my source guides.
Raycaster
Game
Claude Opus 5 7.8
·
Fugu Ultra 1.1 2.0
(+5.8)
What I saw: Strong polished HUD, minimap, weapon model and full combat framework (12 hostiles, purge objective) plus textured walls—but the screenshot shows no visible enemies and an overly blurry/washed corridor, so it reads more atmospheric than a crisp Wolfenstein maze. Shippable and abov…
Neoncity
Game
Claude Opus 5 7.4
·
Fugu Ultra 1.1 2.3
(+5.1)
What I saw: Strong polished HUD (hull/boost/speed/kills/hostile), a nicely modeled neon vehicle with soft shadow, and a coherent purple cyberpunk street with lane dashes and neon strips — but the scene reads sparse and dim, the neon-lit density is modest, and no enemies/combat are visible in…
Aurora
Visual
Claude Opus 5 8.6
·
Fugu Ultra 1.1 5.5
(+3.1)
· cinematic aurora scene
What I saw: Gorgeous WebGL curtains with realistic vertical streaks, layered mountains, starfield and water reflection make this a full cinematic scene; polished palette switcher and typography plus reflection depth push it past the field's best.
Nordiccrypt
Game
Claude Opus 5 8.0
·
Fugu Ultra 1.1 5.2
(+2.8)
What I saw: Strong first-person crypt crawler with a clear enemy (Crypt Shade with health bar) approaching, first-person axe viewmodel, HUD with health/vigor/kills/minimap, and a torch-lit chandelier — combat is present and shippable. Weak points: the scene reads as dim beige boxes rather th…
Dragonflight
Game
Claude Opus 5 8.2
·
Fugu Ultra 1.1 6.5
(+1.7)
What I saw: Gorgeous stylized dragon with articulated wings, spine and belly plates plus a polished full HUD (hull/fury/alt/spd/combo, rings, kills, hostiles, distance marker) — clearly shippable and combat-ready with 5 hostiles tracked. Held back from the top by no visible neon rings or ene…
Where Fugu Ultra 1.1 beat Claude Opus 5
The tasks where I gave Fugu Ultra 1.1 a higher 0–10 score on the same prompt — with the actual commentary from my source guides.
Doom
Game
Fugu Ultra 1.1 8.4
·
Claude Opus 5 6.8
(+1.6)
· 3D demon shooter
What I saw: Strong atmospheric 3D maze with a visible horned demon enemy, working shotgun, minimap with tracked enemies, and active combat ('CLAWED' hit feedback, HP dropped to 082) — polished HUD and lighting. Falls just shy of the field's best; enemies are more Three.js models than true ra…
Neonblaster
Game
Fugu Ultra 1.1 8.2
·
Claude Opus 5 6.8
(+1.4)
What I saw: Polished 3D low-poly arcade shooter with visible enemies, active combat state (score 238, kills 1, health 75, 5 enemies), power-up pickups, crystals/asteroids scenery and a clean neon HUD — clearly functional and juicy; slightly generic ground-based feel rather than a true space …
Twilightvale
Game
Fugu Ultra 1.1 8.6
·
Claude Opus 5 7.3
(+1.3)
· Atmospheric RPG World
What I saw: Gorgeous cohesive twilight scene with detailed hero holding a weapon, visible enemies (creature + humanoid), wooden bridge, lampposts, cottage, river, pickups and a working minimap/HUD with quest and kill tracker. Strong art direction and populated world with combat framing; only…
Dragonrealm
Game
Fugu Ultra 1.1 8.6
·
Claude Opus 5 8.3
(+0.3)
· Frozen combat realm
What I saw: Strong Skyrim-vibe frozen open world with layered snowy mountains, a player with visible sword, multiple approaching enemies with health orbs, runes, an event banner ('DRAGON SWOOP · FIRE BREATH') and polished HUD/compass — clearly beats the empty-walking-sim trap. Enemy models a…
Strengths & weaknesses I logged
Claude Opus 5
Strengths
- Frontier-class coding + agentic reasoning (Claude 5 family)
- 1M-token context — reads an entire codebase in one call
- Benched here with skill-infused game prompts the day of release
Trade-offs
- Premium pricing ($5/$25 per M) — route the everyday 90% to cheaper lanes
- Reasoning-by-default eats token budgets unless tuned per call
Fugu Ultra 1.1
Strengths
- Orchestrates 1-3 expert agents per request and synthesises their answers
- Reported SWE-Bench Pro 73.7 — above Opus 4.8 and GPT-5.5 on Sakana's table
- OpenAI- and Anthropic-compatible API — drop-in for Codex and Claude Code
Trade-offs
- Benched as a partial run until the full 50-task batch completes
- Region-locked: unavailable across the EU/EEA/UK/CH — access depends on where you are
Pricing & context — the spec sheet
| Spec | Claude Opus 5 | Fugu Ultra 1.1 |
|---|---|---|
| Vendor | Anthropic | Sakana AI |
| Context window | 1,000,000 tokens | 1,000,000-token context window |
| Price | $5 / $25 per M | API · orchestration billed |
| Pricing detail | Anthropic's brand-new flagship — the first Opus of the Claude 5 family, with a 1M-token context window. Benched via API the day it dropped; game tasks use our skill-infused AAA build prompts. | Sakana's Fugu Ultra v1.1 — a multi-agent system served as a model: an orchestrator routes each request across one to three expert agents and synthesises the answer. Reported (v1.0): SWE-Bench Pro 73.7, LiveCodeBench 93.2, GPQA Diamond 95.5. NOTE: Sakana geo-blocks the EU/EEA/UK/Switzerland pending GDPR compliance — benched from an allowed region. |
| Release | 2026-07 | 2026-07 |
| Bench coverage | 50/50 scored · avg 8.27/10 | 23/24 scored · avg 6.94/10 |
The verdict — which should you pick?
Across 23 scored shared tasks, Claude Opus 5 averaged 8.00/10, beating Fugu Ultra 1.1's 6.94/10 by 1.05 points. Pick Claude Opus 5 when the build has to ship on the first prompt and you can afford the trade-offs in the comparison below.
If you only run one of these inside your stack, the head-to-head average above is the call. If you can run both, my honest play is to wire Claude Opus 5 and Fugu Ultra 1.1 both into the Agent Operating System and dispatch each from the kanban by task type — hardest agentic builds → Claude Opus 5, hard, high-stakes coding and reasoning where answer quality beats latency → Fugu Ultra 1.1. That's the same setup I run for the 4,000+ founders inside the AI Profit Boardroom.
FAQ — Claude Opus 5 vs Fugu Ultra 1.1
Which is better, Claude Opus 5 or Fugu Ultra 1.1?
On Goldie Bench, Claude Opus 5 averages 8.00/10 across the shared tasks, with 13 gold, 7 silver, 5 bronze overall. Fugu Ultra 1.1 averages 6.94/10, with 0 gold, 1 silver, 2 bronze. Claude Opus 5 wins the head-to-head 18–4.
How much does Claude Opus 5 cost vs Fugu Ultra 1.1?
Claude Opus 5: Anthropic's brand-new flagship — the first Opus of the Claude 5 family, with a 1M-token context window. Benched via API the day it dropped; game tasks use our skill-infused AAA build prompts. Fugu Ultra 1.1: Sakana's Fugu Ultra v1.1 — a multi-agent system served as a model: an orchestrator routes each request across one to three expert agents and synthesises the answer. Reported (v1.0): SWE-Bench Pro 73.7, LiveCodeBench 93.2, GPQA Diamond 95.5. NOTE: Sakana geo-blocks the EU/EEA/UK/Switzerland pending GDPR compliance — benched from an allowed region.
What's the context window for Claude Opus 5 vs Fugu Ultra 1.1?
Claude Opus 5 has a 1,000,000 tokens context window. Fugu Ultra 1.1 has a 1,000,000-token context window context window.
When should I pick Claude Opus 5 over Fugu Ultra 1.1?
Pick Claude Opus 5 for: Hardest agentic builds; Whole-repo reasoning; Frontier one-shots. The trade-off is the weaknesses we logged on the bench: Premium pricing ($5/$25 per M) — route the everyday 90% to cheaper lanes; Reasoning-by-default eats token budgets unless tuned per call.
When should I pick Fugu Ultra 1.1 over Claude Opus 5?
Pick Fugu Ultra 1.1 for: Hard, high-stakes coding and reasoning where answer quality beats latency; Agentic workflows in Codex / Claude Code via the drop-in provider config; One-shot builds you want a panel of experts on, not a single model. The trade-off is the weaknesses we logged on the bench: Benched as a partial run until the full 50-task batch completes; Region-locked: unavailable across the EU/EEA/UK/CH — access depends on where you are.
How does Goldie Bench score Claude Opus 5 vs Fugu Ultra 1.1?
Every demo on this page was built by Julian Goldie inside the Agent Operating System — same fixed prompt for both models, one shot, single HTML file out. Each result gets a 0–10 score on whether it ran, how close it hit the brief, and how good it looked. The highest score on each task gets gold; second gets silver; third gets bronze. See methodology for full provenance.
Related comparisons
Other head-to-heads using the same scoring system:
Claude Opus 5 vs Fusion Fugu Ultra 1.1 vs Fusion Claude Opus 5 vs Hermes MoA Fugu Ultra 1.1 vs Hermes MoA Claude Opus 5 vs GPT-5.6 Sol Fugu Ultra 1.1 vs GPT-5.6 Sol Claude Opus 5 vs Claude Fable 5 Fugu Ultra 1.1 vs Claude Fable 5Full model pages: Claude Opus 5 · Fugu Ultra 1.1 · back to the leaderboard
The same stack Julian uses
Run this stack yourself.
Every demo on this bench was built inside the Agent Operating System — one prompt, one shot, single HTML file out. The Agent OS, the prompts, the templates, the weekly walkthroughs and 4,000+ founders shipping with it every day all live inside the AI Profit Boardroom.
4,000+founders
258documented wins
38countries
$59/momonthly