MODEL VERSIONS ON THIS PAGE HAVE MOVED — CHECKED 8 OCTOBER 2026
Current line, with published API pricing per million tokens:
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OpenAI — GPT-6 Sol (paid ChatGPT), GPT-6 Luna ($0.10 / $0.50), GPT-6.1 Sol ($2.00 / $10.00), GPT-6 Astra
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Anthropic — Claude Opus 5.5, Sonnet 5.5 ($2.00 / $10.00), Haiku 5.5 ($0.10 / $0.50 below 100K), Fable 5.1
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xAI — Grok 4.3 ($1.25 / $2.50), Grok 4.7 ($2.00 / $6.00)
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Google — Gemini 3.5 Flash-Lite ($0.30 / $2.50), Gemini 3.8 Flash ($0.75 / $3.75 to 31 Dec), Gemini 4 Argon
The comparison below is kept because the reasoning still holds — how these tiers trade price against capability has not changed. The version numbers and prices have.
Current pricing table →
QUICK VERDICT — JULY 26, 2026
● Cheaper: Muse Spark 1.1 — $1.25/$4.25/M vs Opus 5 $5/$25/M (75% cheaper input)
● Better parallel agents: Muse Spark 1.1 — parallel sub-agent orchestration built in
● Better writing: Claude Opus 5 — Anthropic's consistent advantage
● Global availability: Claude Opus 5 — Muse Spark API is US-only preview
● Safety rating: Opus 5 (C+) vs Muse Spark (D+, excluded from White House framework)
● SDK compatibility: Both — Muse Spark is OpenAI/Anthropic SDK drop-in
● Weights: Muse Spark closed — Opus 5 also closed
Muse Spark 1.1 for: Cost-sensitive agentic workflows (75% cheaper input), parallel sub-agent orchestration, US teams evaluating a third frontier API option. SDK drop-in means the test is cheap — just change base URL and model string.
Claude Opus 5 for: Writing quality, global availability (non-US teams), regulated industries where Meta's D+ FLI safety rating or exclusion from the White House framework creates governance risk, and production workloads needing Anthropic's auto-fallback rather than hard refusals.
Last updated July 26, 2026. Related: Muse Spark 1.1 full review → · Claude Opus 5 full review →