Drift Check

Compare the current state of an investigation scope against a prior snapshot and report what moved. There is no running process: this reads the versioned files (.product-eval/<scope>/snapshots/ and git history) on demand.

Workflow

1. Pick scope and baseline

Choose the investigation scope and the baseline to compare against, a prior snapshot in .product-eval/<scope>/snapshots/, or a git ref.

2. Diff the artifacts

• Problem statement: has it drifted from the evidence that supports it?
• Evidence: items added or removed; total weight change; anything newly retired as stale (e.g. by a changelog check).
• Themes: new, faded, or merged.
• Scores: Value and Confidence movement, with drivers.
• Brief / narrative: has the framing been reworded or reframed?

3. Run consistency checks

Apply the cross-stage consistency checks from ../pressure-test/references/critic-checklist.md: problem-statement drift, persona drift, vanity-metric creep, scope vs evidence proportionality, and circular reversals in the decisions log.

4. Report the confidence trajectory

The key signal: is evidence accumulating (Confidence rising as real data arrives) or are you spinning (churn without new evidence)? Say which.

Output

A short "what moved since <baseline>" summary: scores up/down with drivers, evidence added/retired, problem or narrative drift flags, consistency violations, and the confidence trajectory. Append it to the decisions log. End with Next move: and recommend re-running readiness, refreshing evidence, or updating the brief/build brief if the decision changed.

Scheduled use

Can run as a weekly scheduled task, "what moved this week across my investigations", as a digest, not a service. Offer to set one up when the user tracks an investigation over time.