Why now
Models change. Your product shouldn't.
The model behind your product is not permanent. Providers retire old versions, serving behavior can drift, and lower-cost alternatives appear constantly. Switching without evidence risks regressions. Refusing to switch means continuing to overpay.
Forced migrations
Providers retire models on fixed deadlines. Your team has to move before production requests begin failing.
Silent behavior changes
Infrastructure and serving changes can alter model behavior even when your application code has not changed.
Expensive inertia
A cheaper model may already handle your workload. Without a trustworthy test, the savings remain locked behind migration risk.
The platform
One test. A defensible decision.
Test what your customers actually use.
Import production traces from your existing observability stack, connect a lightweight recorder, or generate a starter suite from your prompts and documents. ACSI organizes the workload into representative test cases instead of relying on generic benchmarks.
- Existing traces and exports
- Lightweight recording
- Starter suite generation
- Stratified workload coverage
Illustrative: example workload sources.
Measure the model's natural wobble first.
The same model can return different answers to the same request. Before comparing replacements, ACSI tests the current model against itself and measures its normal run-to-run variation. Only degradation beyond that noise floor affects the verdict.
Without a control group, a model comparison can mistake normal variation for a real regression.
Current model vs. itself, across 5 runs per selected case.
Illustrative: normal variation vs. a real regression.
Find the cheapest model that passes.
ACSI starts with the lowest-cost viable candidate and stops at the first pass. Each candidate is tested with your existing prompts and then tested again with prompts adapted to the replacement model. The resulting prompt patches are included in the migration package.
- Cheapest viable candidate first
- Existing prompts tested unchanged
- Model-specific prompt adaptation
- Reviewable prompt diffs and holdout validation
Search stopped at first passing candidate.
Candidate B detail
Illustrative: generic candidate names.
Ship the evidence, not a guess.
The result is a conservative PASS or BLOCK verdict against your own requirements, at stated coverage and confidence. The report shows what passed, what failed, what changed, how much the swap could save, and exactly what was not tested.
A PASS is evidence against the stated test scope and customer rules. It is not a guarantee of error-free production behavior.
Illustrative: example verdict values.
Continuous assurance
The migration ends. The test keeps watching.
The workload suite created for the migration stays installed as a permanent tripwire. ACSI reruns it on a schedule and alerts your team when the current model's behavior changes, or when a cheaper candidate clears your bar.
Migration is the event. Monitoring is the subscription.
- Jul 2Baseline established
- Jul 5No material change
- Jul 8Format regression detected
- Jul 8Alert sent to on-call
- Jul 10Baseline restored
New candidate detected
Security
Your workloads stay under your control.
ACSI scrubs sensitive fields before evaluation and limits each run to the providers and environments you approve. Where supported, the full test can execute inside your existing cloud environment.
Sensitive-data scrubbing
Names, emails, credentials, API keys, and configured secrets are removed before testing.
Approved providers only
Raw workloads are never sent to a model provider the customer has not approved.
In-environment execution
Where supported, tests run through models available inside the customer's AWS, Azure, or Google Cloud environment.
Controlled retention
Evaluation inputs, outputs, reports, and retention policies are visible and configurable.
Replayed in your environment. Evidence comes out.
Methodology
Built to separate real regressions from noise.
Calibrated baseline
The current model is tested against itself before any replacement is judged.
Customer rules first
Schemas, required facts, executable code, format requirements, and other deterministic assertions outrank subjective scores.
Independent judging
Subjective cases use judges that are independent from the candidate models, with human calibration reported alongside them.
Explicit uncertainty
Every result states its test count, coverage, confidence, assumptions, and exclusions.
Pay for the migration. Keep the alarm.
ACSI is priced per certified model swap, with optional continuous monitoring afterward. Model inference used during testing is passed through separately.
Find out whether you can switch before you risk it.
Test a lower-cost model against the workloads and rules that matter to your product.
