Standard Compute
Model comparison 2026

Claude Opus 5.5 vs Muse Spark Open

Claude Opus 5.5
Anthropic · Frontier · Proprietary
$8.80/1M · 1M ctx
Muse Spark Open
Meta · Balanced · Open weights
$2.15/1M · 1.0M ctx

Community vote

Pick a winner in each dimension. You can change your vote any time.

Output Quality

Correctness and depth of what it produces

Agentic Ability

Tool calls, instruction-following, and multi-step tasks

Speed

Tokens per second and time-to-first-token

Value for Money

How much capability you get per dollar

Reliability

Consistent results: fewer refusals, loops and format breaks

Specs and pricing side by side

Spec
Opus 5.5
Muse Spark Open
Maker
Anthropic
Meta
Blended price / 1M
$8.80
$2.15
Input / output
$4.00 in · $20 out / 1M tokens
$1.25 in · $4.25 out / 1M tokens
Context window
1M
1.0M
Open weights
No
Yes
Tool use
Yes
Yes
Reasoning
Yes
Yes
Output Quality
10.0
7.0
Agentic Ability
10.0
5.0
Speed
7.6
7.0
Value for Money
5.7
5.3
Reliability
9.5
8.0

Pricing and capabilities synced from the OpenRouter catalogue. Scores are editorial (0–10).

Verdict: Opus 5.5 or Muse Spark Open?

Updated 2026-10-16

Choose Claude Opus 5.5 if you want the hardest coding and agent steps, with Sonnet 5.5 handling routine work. Choose Muse Spark Open if you want trying Meta's open-weight coding model through OpenRouter, or self-hosting it where code must stay on your own hardware.

In our editorial scoring, Claude Opus 5.5 leads in 5 of five dimensions (output quality, agentic ability, speed, value for money and reliability), while Muse Spark Open leads in 0. On price, Claude Opus 5.5 runs about $8.80 per 1M tokens (blended) and is proprietary; Muse Spark Open is about $2.15 and open-weight.

Where Opus 5.5 falls short
  • Costs twice Sonnet 5.5 per request ($0.107 vs $0.053) for a small measured gain
  • Sonnet 5.5 scores higher in Artificial Analysis's Terminal-Bench 4.0 run (63.6% vs 59.6%)
Full Opus 5.5 breakdown →
Where Muse Spark Open falls short
  • No independent agent benchmark results yet; the published figures are Meta's own
  • Self-hosting needs at least 700 GB of GPU memory in NVFP4 (2 TB in BF16), per Meta's model card
Full Muse Spark Open breakdown →

Setting it up? Claude Opus 5.5: model ID, providers and agent config

The agent matters as much as the model. Compare AI agents →

Current Claude, GPT, Gemini and open models run on Standard Compute

Standard Compute

Current frontier models Claude Fable 5.1 · GPT-6 Astra

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