Model comparison

Claude Opus 5 vs Muse Spark 1.2

Anthropic against Meta, compared on context, price, and attributed benchmark results.

Recorded profile verification October 2, 2026Individual provider fields may changeEvidence confidence: Medium — see receipts below

Anthropic

Claude Opus 5

Frontier

Meta

Muse Spark 1.2

Frontier

AI model capability comparison
Specification	Claude Opus 5	Muse Spark 1.2
Provider
Provider	Anthropic	Meta
Tier
Tier	Frontier	Frontier
Context window
Context window	1M	Winner: 1.05M
Max output
Max output	128K	Not verifiedUnverified
Input / 1M tokens
Input / 1M tokens	$5	Winner: $1.25
Output / 1M tokens
Output / 1M tokens	$25	Winner: $4.25
Weights
Weights	Closed	Closed
Parameters
Parameters	Not verifiedUnverified	Not verifiedUnverified
Reasoning levels
Reasoning levels	low, medium, high, xhigh, max	minimal, low, medium, high, xhigh
Modalities
Modalities	text, image	text, image, video, audio, pdf
API model id
API model id	claude-opus-5	muse-spark-1.2
Released
Released	July 24, 2026	August 5, 2026
Humanity's Last Exam · source date Claude Opus 5: 2026-09-01
Humanity's Last Exam · source date Claude Opus 5: 2026-09-01	63.6	Not verifiedUnverified
Terminal-Bench 2.1 · source date Claude Opus 5: 2026-09-02
Terminal-Bench 2.1 · source date Claude Opus 5: 2026-09-02	89.1	Not verifiedUnverified

Dates beside benchmark scores refer to the linked source’s publication or capture date unless that source explicitly states when it measured the result. A shared URL alone does not establish comparable runs; unverified setups are marked. Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

Source date2026-09-02
Google Gemini 3.8 Flash evaluation table quoting public leaderboard / Artificial Analysis, Terminus 2; not a Google-run Opus evaluation (Cross-provider quotation; common effort and experiment date unverified)
Agentic terminal work: multi-step tasks executed in a sandboxed shell environment.
Comparable with caveatNot comparable with Terminal-Bench 3.0 or 4.0 (different task sets) or v1; harness configuration (container, time limits) also shifts results.
Source date2026-09-01
Anthropic Fable 5.1 comparison table (vendor, with tools; 56.6 no tools)
Frontier-knowledge ceiling: extremely hard multi-domain questions written to be near-impossible without deep expertise.
Comparable with caveatSubset/tool configurations (text-only vs with-tools) differ between vendors and materially change scores; must match configuration to compare.

Pricing tiers

Claude Opus 5: Standard $5/$25 per MTok with no long-context surcharge. Cache reads $0.50; 5-minute writes $6.25 and 1-hour writes $10. Batch $2.50/$12.50. First-party Fast research preview $10/$50, unavailable with Batch. US-only inference adds 10% where supported. Batch 300K output requires output-300k-2026-03-24; standard stays 128K. Knowledge cutoff May 2026; retirement not sooner than July 24, 2027.

Muse Spark 1.2: Meta Standard $1.25/$4.25 per MTok, cached $0.15; no long-context premium. Separate muse-spark-1.2-contributor is $0.10/$0.20, cached $0.002, granting training permission for prompts/completions. Search grounding adds $2.50 per 1,000 queries.

FrontierRecord checked October 1, 2026

Claude Opus 5

Claude Opus 5 is Anthropic's July 2026 agentic-coding model, now 'Active (legacy)'. Its successor Opus 5.5 has lower base input/output prices ($4/$20 vs $5/$25 per million tokens); performance depends on the workload and evaluation settings.

Best for

Complex agentic coding
Enterprise work
Long-context analysis

Watch out

Active legacy, superseded by Opus 5.5. Test migration: Opus 5.5 makes adaptive thinking always on, rejects forced tool use and the older computer-use tool, and changes thinking-block/progress behavior. Partner cloud lifecycles and prices can differ.

FrontierRecord checked October 2, 2026

Muse Spark 1.2

Muse Spark 1.2 is Meta's previous version, still listed on the Model API alongside the 1.3 refresh.

Best for

Frontier reasoning
Meta ecosystem
Agentic work

Watch out

Closed weights and still in the current public catalog. Minimal/low/medium/high/xhigh are supported; none returns HTTP 400. Max is restricted to Standard Spark 1.3. Audio is listed without 1.3's degradation warning. Reasoning counts toward output budget and billing. Exact hard output cap and parameter count remain unverified; quotas are per team.

When the cheaper one wins

Muse Spark 1.2 is cheaper on output at $4.25 per million tokens against $25 for Claude Opus 5 — about 5.9×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. On DeepSWE 1.1, Muse Spark 1.2 is 54.9% Pass@1 at $3.7/task versus Claude Opus 5 at 73.6% / $11.84/task. This compares standard short-context token rates, not total cost per accepted task. Include input, cache, context tiers, schedules, retries and review in your pilot.

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Evidence confidence: Medium

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

Pricing verified on both sides — Input and output rates are verified for both models.
3/5 core specs verified on both sides — Not published for at least one side: max output, parameter count.
No directly aligned benchmark setup — No benchmark has matching cited sources, source dates, units, effort and recorded run details on both models.
Verified within the last 90 days — Older of the two catalog checks was 25 days ago.
Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Claude Opus 5: Claude model overview — whole-profile source check October 1 (accessed 2026-10-01)
Claude Opus 5: Claude current API pricing, caching and inference geography (accessed 2026-10-01)
Claude Opus 5: Anthropic — Claude Opus 5 (accessed 2026-08-29)
Claude Opus 5: Anthropic news — Claude Opus 5 (accessed 2026-08-29)
Claude Opus 5: Anthropic — Claude Opus 5.5 (Opus 5 successor) (accessed 2026-09-26)
Claude Opus 5: Anthropic selectable effort levels (separate from adaptive thinking mode) (accessed 2026-10-01)
Muse Spark 1.2: Meta — Models (accessed 2026-10-01)
Muse Spark 1.2: Meta — Reasoning (accessed 2026-10-01)
Muse Spark 1.2: Meta — Pricing and rate limits (accessed 2026-10-01)
Muse Spark 1.2: Meta — Introducing Muse Code and Muse Spark 1.2 (accessed 2026-10-01)
Muse Spark 1.2: Meta — Chat completions schemas (accessed 2026-10-01)

Related comparisons

Diving deeper on one model? Claude Opus 5 · Muse Spark 1.2

Common questions

Claude Opus 5 vs Muse Spark 1.2

Answered from the verified figures on this page rather than general guidance.

Is Claude Opus 5 or Muse Spark 1.2 cheaper for input?

Muse Spark 1.2 is cheaper at $1.25 per million input tokens, against $5 for Claude Opus 5 — roughly 4.0× the price. Estimate both input and output token volume for your workload. These are base rates; Claude Opus 5: Standard $5/$25 per MTok with no long-context surcharge. Cache reads $0.50; 5-minute writes $6.25 and 1-hour writes $10. Batch $2.50/$12.50. First-party Fast research preview $10/$50, unavailable with Batch. US-only inference adds 10% where supported. Batch 300K output requires output-300k-2026-03-24; standard stays 128K. Knowledge cutoff May 2026; retirement not sooner than July 24, 2027. Muse Spark 1.2: Meta Standard $1.25/$4.25 per MTok, cached $0.15; no long-context premium. Separate muse-spark-1.2-contributor is $0.10/$0.20, cached $0.002, granting training permission for prompts/completions. Search grounding adds $2.50 per 1,000 queries.

Is Claude Opus 5 or Muse Spark 1.2 cheaper for output?

Muse Spark 1.2 is cheaper at $4.25 per million output tokens, against $25 for Claude Opus 5 — roughly 5.9× the price. Estimate both input and output token volume for your workload. These are base rates; Claude Opus 5: Standard $5/$25 per MTok with no long-context surcharge. Cache reads $0.50; 5-minute writes $6.25 and 1-hour writes $10. Batch $2.50/$12.50. First-party Fast research preview $10/$50, unavailable with Batch. US-only inference adds 10% where supported. Batch 300K output requires output-300k-2026-03-24; standard stays 128K. Knowledge cutoff May 2026; retirement not sooner than July 24, 2027. Muse Spark 1.2: Meta Standard $1.25/$4.25 per MTok, cached $0.15; no long-context premium. Separate muse-spark-1.2-contributor is $0.10/$0.20, cached $0.002, granting training permission for prompts/completions. Search grounding adds $2.50 per 1,000 queries.

Which has the larger context window, Claude Opus 5 or Muse Spark 1.2?

Muse Spark 1.2 accepts 1.05M tokens against 1M for Claude Opus 5. This only matters if you routinely send very long documents or large codebases.

Do Claude Opus 5 and Muse Spark 1.2 support the same reasoning levels?

Claude Opus 5 exposes low, medium, high, xhigh, max, while Muse Spark 1.2 exposes minimal, low, medium, high, xhigh.

Should I use Claude Opus 5 or Muse Spark 1.2?

Both are classified in our frontier tier; this editorial grouping does not imply equal capability. Claude Opus 5 is a candidate for complex agentic coding; Muse Spark 1.2 is a candidate for frontier reasoning. Compare accuracy, tool reliability, latency and cost on representative tasks.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

Input price: Muse Spark 1.2 costs $1.25 per 1M tokens versus $5 for Claude Opus 5 — a 4x difference at the headline tier.
Context: Muse Spark 1.2 takes 1.05M against 1M for Claude Opus 5 — only decisive if your prompts approach the smaller window.

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