Purple-team work is an evidence handoff, not a spectacle

A purple-team exercise creates value when an authorised test produces evidence the defensive team can inspect and an owner can improve. Technique coverage alone is not the outcome. The useful unit is a traceable handoff from scope, to benign validation, to observed telemetry, to an owned change.

Write the boundary before the test

• Named assets, identities, destinations, time window and exclusions.
• Exercise owner, technical controller, detection owner and stop authority.
• Benign fixtures or simulations that avoid confidential data and production impact.
• Expected telemetry, retention period and evidence location.
• Stop conditions, rollback steps and an escalation contact.

Separate expected, observed and missing evidence

Before validation, write down the event fields and alerts you expect. During review, record what arrived without changing the expectation after the fact. Missing evidence may reveal telemetry, correlation, context or process gaps; those are different problems and should receive different owners.

Close with an owned improvement

For every material gap, name one change, an accountable owner, a due date and a repeatable validation method. A detection that was edited but never retested is unfinished. Keep the original evidence so the improvement can be compared with the baseline.

Use ATT&CK as a shared vocabulary

MITRE ATT&CK helps teams describe adversary behaviours and organise emulation or detection work. It does not grant permission to test and it does not prove coverage by itself. Pair technique IDs with local scope, data sources, expected observations and decision ownership.