ANSWER
What is an evidence pack in a legacy system shutdown?
Reviewed .
An evidence pack is the set of evidence that supports the decision to shut down a legacy system: the result of the parallel-run period (inputs, outputs and measured agreement), every variance classified with an owner and a decision, human approvals with names and dates, and a tested rollback plan. It exists to answer one question: if anyone challenges the cutover later — an auditor, a customer or your own team — the answer is written down, with data, not stored in the memory of whoever was there.
Step by step
- Freeze the equivalence contract before measuring: what must match, tolerances and what counts as a blocker.
- Attach the dual-run result: volume processed, agreement per field and the period covered.
- Record every variance with a classification (new-system error, legacy error, unmapped rule), an owner and a decision.
- Include approvals with name, role and date — including the final cutover authorization.
- Close with the rollback plan: trigger, steps, owner and a tested reversal window.
How an agent does this
At AgenticosCore the evidence pack is assembled from the Trail: every Parallel run records input, output, exceptions and approvals, and the dossier is built from that record — not from the memory of whoever was there. The editable template with the expected structure lives at /en/resources/evidence-pack-template/.
Frequently asked questions
Is an evidence pack only for audits?
No. It serves the decision first: without organized evidence, the go/no-go becomes opinion. Audit is the second use.
Who assembles the evidence pack?
The Trail records; the process owner assembles the pack from it, reviews and signs. That is what the template formalizes — instead of a spreadsheet reconstructed from memory afterwards.
What invalidates an evidence pack?
Aggregate numbers without a defined period, unclassified variances and approvals without names. If you cannot answer who decided and based on what, it is not evidence.
Primary sources
- AI Risk Management Framework — Core — NIST
- Retiring service components securely — UK Government Security