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 5.5 vs Gemini 3.8 Flash for Regulated data on a budget, as of 2026-09-23

Find the cheapest offering with the data-handling commitments regulated workloads need.

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 5.5 has a 31% chance of matching or beating Gemini 3.8 Flash 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: answered. 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.

HIPAA-ready offerings; cheapest first, quality kept.

Requirements

• offering.data.trains_on_customer_data = No: Customer prompts and outputs must not be available for model training.
• offering.data.zero_retention = Yes: The provider must offer a mode that stores neither prompts nor outputs.
• offering.attestation.baa = Yes: The provider must offer a HIPAA business associate agreement for the service.

Preferences

• -offering.cost_per_task: Prefer the lower task cost after the compliance gates pass.
• chat_preference: Keep a quality signal so a cheap but poor assistant does not win on cost alone.

Evidence for Claude Opus 5.5

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.attestation.soc2: not_disclosed
• offering.router_slug: unknown
• offering.speed.throughput: unknown
• offering.speed.time_to_first_token: unknown

Evidence for Gemini 3.8 Flash

Missing facts for Gemini 3.8 Flash

• 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.attestation.soc2: not_disclosed
• offering.router_slug: unknown
• offering.speed.throughput: unknown
• offering.speed.time_to_first_token: unknown

What this template teaches

The gates are the same as the other tiers; only the ranking moves toward cost.

Decision dec_dec45b7d93983dd1d411f74a 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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Use-case examples · Model comparisons · How we decide