Table of contents
In this article
Technical page · Models
Evaluation in CI and production
Regression gates, canaries, drift and rollback
- Published
- 8 November 2026
- Last reviewed
- 8 November 2026
- Re-checked every
- 180 days
- Reviewed by
- Ales Analytics engineering
- Used in
- Reporting engines
In one paragraph
Evaluation does not stop at launch. In continuous integration, every change to a prompt, model, adapter or retrieval setting runs the frozen test set, and a regression beyond an agreed threshold blocks the release. In production, new versions run in shadow and then on a small share of traffic, drift signals are watched, a sample of outputs is reviewed by people, and rollback is a configuration change.
How it works
- Regression gates. Thresholds per metric and per segment (document type, field, question type), not only an overall score.
- Shadow releases. The candidate receives real traffic and logs outputs without serving them; outputs are compared with the live version.
- Canary releases. The candidate serves a small share of traffic, widened as metrics hold.
- Drift signals. Changes in input mix, confidence distributions and review-queue volume, which usually move before accuracy visibly drops.
- Sampled review. A fixed weekly sample reviewed by people; disagreements are added to the test set as a new version.
- Rollback. The previous model, adapter, prompt and index stay deployable.
Design choices and trade-offs
| Choice | Trade-off |
|---|---|
| Strict vs loose thresholds | Strict thresholds block noise as well as regressions; thresholds are set from the confidence intervals of the test set |
| Shadow traffic with content | Best comparison; must follow the same retention rules as production logs |
When not to use it
A system that never changes would not need it, but models, documents and rules all change.
How we evaluate it
By drills: deliberately ship a degraded candidate to a staging environment and confirm the gate blocks it.
Sources
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