Scientist Pattern

Purpose

Reduce migration risk by running old and new paths side-by-side before switching production behavior.

Core loop

1. Define parity contract (inputs, outputs, tolerances).
2. Run champion and challenger on same input window.
3. Compare and persist metrics.
4. Gate promotion on agreed thresholds.
5. Keep rollback path until burn-in is complete.

Minimum outputs

• explicit metric contract
• comparison result per run
• audit trail of pass/fail and deltas
• promotion decision with evidence