ModelSpec is an analysis of alternatives for AI models: it decides which models fit a job from your requirements, sourced benchmarks and real cost, and shows its work.

Claude Opus 4.7 vs Claude Opus 5.5 for Coding (best available), as of 2026-09-23

Find the active coding model with the strongest software-engineering evidence, whatever it costs.

Worked example as of 2026-09-23, from the public data image.

What the evidence says

The evidence can't separate them for this job.

Claude Opus 4.7 has a 26% chance of matching or beating Claude Opus 5.5 on this job's objective.

probability bands: a model joins the leader when P(its score >= the leader's) >= 0.25 under the score posteriors; a weighted capability with an 80% interval wider than 2.8 is not enough evidence

Decision status: partial. P(best) and score intervals retain the full ranked lineup for this job, including models beyond this pair and models with thin evidence. Models with unknown objective values remain unranked and are outside this probability. P(best) is not a head-to-head probability.

Scores and score intervals use the objective's dimensionless normalised units. Cost per task is in USD for the selected offering and the applied spec's task size. When task size is omitted, the engine uses its documented default. Unavailable means the engine returned no value.

Model	Score	Score interval	P(best), ranked job lineup	Cost per task, USD	Selected offering: provider / region / tier	Capability estimates and intervals
Claude Opus 4.7	0.784952	[0.517382, 1.052522]	4%	0.3	anthropic / global / standard	software_engineering: 0.711822213; interval [-0.020952777, 1.444597204]; benchmarks 5; direct benchmarks 2
Claude Opus 5.5	1.0	[0.661373, 1.338627]	21%	0.24	anthropic / global / standard	software_engineering: 1.300758259; interval [0.373384859, 2.22813166]; benchmarks 4; direct benchmarks 2

Strongest coding evidence, cost no object.

Requirements

model.class = text-generator: Coding work needs a model that generates text and code.
model.lifecycle = active: An active model is still supported by its lab or provider.

Preferences

software_engineering: Rank only by the software-engineering capability estimate.

Applied template spec

spec_version

where

model.class = text-generator
model.lifecycle = active

optimize

weights

software_engineering: 1.0

Evidence for Claude Opus 4.7

Benchmark	Version	Measurement	Unit	Published interval	Evidence date	Measurement conditions	Provenance
arena_sc_coding	text_style_control / coding, latest split, revision 1880dbebff5b	1551.79	Arena score (Elo scale)	Unavailable	2026-09-13	Effort: Unavailable Subcategory: Unavailable Harness: Unavailable Measured by: independent_evaluator Sample size: Unavailable	Source
arena_sc_industry_software_it_services	text_style_control / industry_software_and_it_services, latest split, revision 1880dbebff5b	1540.9	Arena score (Elo scale)	Unavailable	2026-09-13	Effort: Unavailable Subcategory: Unavailable Harness: Unavailable Measured by: independent_evaluator Sample size: Unavailable	Source
arena_webdev	webdev / overall, latest split, revision 1880dbebff5b	1555.64	Arena score (Elo scale)	Unavailable	2026-09-23	Effort: Unavailable Subcategory: Unavailable Harness: Unavailable Measured by: independent_evaluator Sample size: Unavailable	Source
frontiercode_v1_1	FrontierCode 1.1, main score (Mean@5)	38.5	percent	Unavailable	2026-09-30	Effort: max Subcategory: Unavailable Harness: unregistered Measured by: benchmark_author Sample size: Unavailable	Source
swe_bench_verified	SWE-bench Verified (Epoch AI run)	83.47	percent	Unavailable	2026-04-20	Effort: max Subcategory: Unavailable Harness: Unavailable Measured by: independent_evaluator Sample size: Unavailable	Source

Missing facts for Claude Opus 4.7

model.hardware_fit_indeterminate: unknown
model.languages: unknown
model.parameters_total: unknown
origin.base_lineage: not_disclosed
origin.weights_hosting: not_disclosed
offering.api_model_id: unknown
offering.data.zero_retention: requires_contract
offering.private_deployment: unknown
offering.router_slug: unknown
offering.speed.throughput: unknown
offering.speed.time_to_first_token: unknown

Evidence for Claude Opus 5.5

Benchmark	Version	Measurement	Unit	Published interval	Evidence date	Measurement conditions	Provenance
arena_webdev	webdev / overall, latest split, revision 1880dbebff5b	1818.41	Arena score (Elo scale)	Unavailable	2026-09-23	Effort: Unavailable Subcategory: Unavailable Harness: Unavailable Measured by: independent_evaluator Sample size: Unavailable	Source
cursorbench_4	CursorBench 4.0	57.8	percent	Unavailable	2026-09-30	Effort: max Subcategory: Unavailable Harness: Unavailable Measured by: benchmark_author Sample size: Unavailable	Source
swe_bench_multilingual	SWE-bench Multilingual	93.9	percent	Unavailable	2026-09-22	Effort: max Subcategory: Unavailable Harness: Unavailable Measured by: provider_self_report Sample size: Unavailable	Source
swe_bench_multimodal	SWE-bench Multimodal	61.4	percent	Unavailable	2026-09-22	Effort: max Subcategory: Unavailable Harness: Unavailable Measured by: provider_self_report Sample size: Unavailable	Source
swe_bench_pro	SWE-bench Pro	89.9	percent	Unavailable	2026-09-22	Effort: max Subcategory: Unavailable Harness: Unavailable Measured by: provider_self_report Sample size: Unavailable	Source
terminal_bench_v4_0	Terminal-Bench 4.0	66.4	percent	Unavailable	2026-09-22	Effort: xhigh Subcategory: Unavailable Harness: Unavailable Measured by: provider_self_report Sample size: Unavailable	Source

Missing facts for Claude Opus 5.5

model.hardware_fit_indeterminate: unknown
model.languages: unknown
model.parameters_total: unknown
origin.base_lineage: not_disclosed
origin.weights_hosting: not_disclosed
offering.api_model_id: unknown
offering.data.zero_retention: requires_contract
offering.private_deployment: unknown
offering.router_slug: unknown
offering.speed.throughput: unknown
offering.speed.time_to_first_token: unknown

What this template teaches

With no cost term, the ranking is capability alone; the canvas still shows what each candidate costs.

Decision dec_0180e89bde9bae9adb9de365 on public snapshot snap_05a963d2477ac2fb.

Read the full dated job answer.

The live board uses current data. This link applies the template to its full lineup.

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