VerdictPal · editorial desk · updated 23 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 Opus 5.5 vs Claude Fable 5.1

Model A

Model B

MODEL A

Claude Opus 5.5

Anthropic · Claude Opus

Composite 0Intel 00 rows0 sources

Anthropic's 22 Sep 2026 Opus. API list $4 / $20 per 1M tokens, 1M context, 128K output. Text and image in, text out. No AA or Vals ledger row on this page as of 23 Sep 2026.

MODEL B

Claude Fable 5.1

Anthropic · Claude Fable

Composite 70Intel 6911 rows2 sources

Anthropic's 1 Sep 2026 Mythos-class refresh of Fable 5. Same $10 / $50 per 1M tokens, cache reads $0.25 per 1M. 1M context, 128K output. Live Vals Index 68.83% — still #1, ahead of Opus 5 and GPT-6 Astra. AA Intelligence Index v4.3 is 53.4 at max + default fallback. Do not compare that 53.4 to the Sept 1 v4.1 headline of 66 or the Sept 5 v4.2 headline of 57.

Claude Opus 5.52stats won

Tied2stats

Claude Fable 5.13stats won

Spec showdown

Capacity, price, freshness.

Claude Opus 5.5vsClaude Fable 5.1

Claude Fable 5.1 leads on composite score (70 vs 0), with deeper benchmark coverage across more families. Claude Opus 5.5 is more affordable at $4.0/1M input — about 3× cheaper than $10/1M.

Composite score
Claude Opus 5.50Claude Fable 5.170Winner on this row
Intelligence (Vals/AA)
Claude Opus 5.50Claude Fable 5.169Winner on this row
Context window
Claude Opus 5.51MClaude Fable 5.11M
Max output
Claude Opus 5.5128KClaude Fable 5.1128K
Input price / 1M (lower wins)
Claude Opus 5.5$4.0Winner on this rowClaude Fable 5.1$10
Output speed (AA default API)
Claude Opus 5.5—Claude Fable 5.170 t/sWinner on this row
Time to first token (AA default API)
Claude Opus 5.5—Winner on this rowClaude Fable 5.1137.02s

Composite score

Intelligence (Vals/AA)

Context window

Max output

128K

Input price / 1M (lower wins)

$4.0

$10

Output speed (AA default API)

—

70 t/s

Time to first token (AA default API)

—

137.02s

Capability grid

What each model can do.

Modalities

Claude Opus 5.5Claude Fable 5.1

Text●●

Image●●

Audio——

Video——

Code●●

Tool use●●

Reasoning●●

Access

Claude Opus 5.5Claude Fable 5.1

API●●

Consumer app●●

Open weights——

Managed cloud●●

On-device——

Family profile

Top score per benchmark family.

No shared benchmark families between these two models.

Benchmark ranks

Every shared benchmark, side by side.

No shared benchmarks found between these two models.

Dossier facts

Dates, sources, fineprint.

Claude Opus 5.5Claude Fable 5.1

ProviderAnthropicAnthropic

FamilyClaude OpusClaude Fable

Release date2026-09-222026-09-01

Knowledge cutoffJun 20262026-06-01

Context window1M1M

Max output128K128K

Input price /1M$4.0$10

Output price /1M$20$50

Statusflagshipsolid

Composite score070

Intelligence score069

Intel sourcenonevals

Benchmark rows011

Source count02

Freshnessstalefresh

Pricing checked2026-09-232026-09-18

Ecosystem

Which tools wrap each model.

Claude Opus 5.5

claude

Claude Fable 5.1

claude

Verdict

Which model to actually pick.

Claude Fable 5.1 leads on composite score (70 vs 0), with deeper benchmark coverage across more families. Claude Opus 5.5 is more affordable at $4.0/1M input — about 3× cheaper than $10/1M.

Open Claude Opus 5.5's dossier Open Claude Fable 5.1's dossier

Questions this comparison answers

Every answer below is assembled from the dated fields on this page. Nothing is written separately for search.

Should you use Claude Opus 5.5 or Claude Fable 5.1?

Claude Fable 5.1 leads on composite score (70 vs 0), with deeper benchmark coverage across more families. Claude Opus 5.5 is more affordable at $4.0/1M input — about 3× cheaper than $10/1M.

Is Claude Opus 5.5 or Claude Fable 5.1 cheaper?

Claude Opus 5.5: $4.0 / $20. Claude Fable 5.1: $10 / $50.

How do the Claude Opus 5.5 and Claude Fable 5.1 context windows compare?

Claude Opus 5.5: 1M. Claude Fable 5.1: 1M.