What does the final go/no-go pack contain?

• Before/after workflow with all remaining manual work.
• Holdout results, unresolved failures and source-link checks.
• Net-effort result including correction and maintenance.
• Confirmed three-year costs and an explicit list of unknowns.
• Data, approval, integration and recovery evidence.
• Named owner, support arrangement and retraining plan.
• Exported sample and documented exit route.
• A written decision: stop, revise, extend observation or release the bounded scope.

Bring in a specialist when ground truth cannot be established internally, the integration crosses financial controls, restricted data is involved, or technical selection requires expertise the team lacks. Specify the deliverable you need; specialist involvement does not itself establish a saving.