VerdictPal · editorial desk · updated 1 Sep 2026VerdictPal

Compare · Two models, head-to-head

Pick two models. See the diff.

Composite scores, benchmark ranks, capability grids, and pricing per million tokens. All sourced from the same data that powers the model atlas.

Tools Models

Claude Fable 5.1 vs Claude Opus 5 (Adaptive Reasoning, Max Effort)

Model A

Model B

MODEL A

Claude Fable 5.1

Anthropic · Claude Fable

Composite 67Intel 683 rows2 sources

Anthropic's 1 Sep 2026 Mythos-class refresh of Fable 5. Same $10 / $50 per 1M tokens, cache reads cut to $0.25 per 1M. 1M context, 128K output, always-on adaptive thinking. Vals Index 67.87% on the 1 Sep 2026 snapshot — ahead of Opus 5 and Fable 5. AA Intelligence Index not in the 1 Sep API snapshot yet.

MODEL B

Claude Opus 5 (Adaptive Reasoning, Max Effort)

Anthropic · Claude Opus

Composite 63Intel 6716 rows5 sources

AA Intelligence Index 60.7. Listed on Artificial Analysis with API pricing $5/$25 per 1M tokens. Benchmark rows sync from the AA snapshot — see the ledger on this page.

Claude Fable 5.15stats won

Tied0stats

Claude Opus 5 (Adaptive Reasoning, Max Effort)2stats won

Spec showdown

Capacity, price, freshness.

Claude Fable 5.1vsClaude Opus 5 (Adaptive Reasoning, Max Effort)

Composite scores are within 5 points — 67 for Claude Fable 5.1 vs 63 for Claude Opus 5 (Adaptive Reasoning, Max Effort). The choice comes down to capability profile and price. Claude Fable 5.1 has the higher Vals/AA intelligence score (68 vs 67). Claude Opus 5 (Adaptive Reasoning, Max Effort) is more affordable at $5.0/1M input — about 2× cheaper than $10/1M. Claude Fable 5.1's 1M context window dwarfs Claude Opus 5 (Adaptive Reasoning, Max Effort)'s 128K — a meaningful difference for long-document or codebase work.

Composite score
Claude Fable 5.167Winner on this rowClaude Opus 5 (Adaptive Reasoning, Max Effort)63
Intelligence (Vals/AA)
Claude Fable 5.168Winner on this rowClaude Opus 5 (Adaptive Reasoning, Max Effort)67
Context window
Claude Fable 5.11MWinner on this rowClaude Opus 5 (Adaptive Reasoning, Max Effort)128K
Max output
Claude Fable 5.1128KWinner on this rowClaude Opus 5 (Adaptive Reasoning, Max Effort)—
Input price / 1M (lower wins)
Claude Fable 5.1$10Claude Opus 5 (Adaptive Reasoning, Max Effort)$5.0Winner on this row
Output speed (AA default API)
Claude Fable 5.1—Claude Opus 5 (Adaptive Reasoning, Max Effort)49 t/sWinner on this row
Time to first token (AA default API)
Claude Fable 5.1—Winner on this rowClaude Opus 5 (Adaptive Reasoning, Max Effort)36.30s

Composite score

Intelligence (Vals/AA)

Context window

128K

Max output

128K

—

Input price / 1M (lower wins)

$10

$5.0

Output speed (AA default API)

—

49 t/s

Time to first token (AA default API)

—

36.30s

Capability grid

What each model can do.

Modalities

Claude Fable 5.1Claude Opus 5 (Adaptive Reasoning, Max Effort)

Text●●

Image●—

Audio——

Video——

Code●●

Tool use●—

Reasoning●●

Access

Claude Fable 5.1Claude Opus 5 (Adaptive Reasoning, Max Effort)

API●●

Consumer app●—

Open weights——

Managed cloud●—

On-device——

Family profile

Top score per benchmark family.

Knowledge

Reasoning

Agentic

Benchmark ranks

Every shared benchmark, side by side.

Reasoning

Artificial Analysis Intelligence Index#1/184 · #2/184

66%

63.1%

Dossier facts

Dates, sources, fineprint.

Claude Fable 5.1Claude Opus 5 (Adaptive Reasoning, Max Effort)

ProviderAnthropicAnthropic

FamilyClaude FableClaude Opus

Release date2026-09-012026-07-24

Knowledge cutoff2026-06-01open

Context window1M128K

Max output128K—

Input price /1M$10$5.0

Output price /1M$50$25

Statussolidsolid

Composite score6763

Intelligence score6867

Intel sourcevalsvals

Benchmark rows316

Source count25

Freshnessfreshfresh

Pricing checked2026-09-012026-07-26

Ecosystem

Which tools wrap each model.

Claude Fable 5.1

claude

Claude Opus 5 (Adaptive Reasoning, Max Effort)

Not listed in any tool yet.

Verdict

Which model to actually pick.

Open Claude Fable 5.1's dossier Open Claude Opus 5 (Adaptive Reasoning, Max Effort)'s dossier