Cross-reference every device inventory the tenant has connected and produce the three lists that matter: devices missing an agent somewhere, orphans that exist in only one tool, and the count deltas per tool — because per-device billing rides on these numbers. This skill changes nothing.
1. Enumerate which inventory sources this tenant actually has enabled, and say which ones the reconciliation will cover: NinjaOne, ConnectWise RMM, Liongard device inventories (its inspectors often carry EDR, backup, and AD/M365 device views that stand in for tools without direct integrations — read the environment's posture for the details), ImmyBot, and documented asset lists in IT Glue / Hudu.
2. Pull the client's device list from each source. Flag any list that may have capped — a truncated list makes every downstream delta wrong, so reconcile per-segment (servers, then workstations, per location) if needed for full coverage.
3. Normalize before matching: hostnames casefolded, domain suffixes stripped, obvious duplicates within a single tool collapsed (same serial, same hostname re-enrolled). Match across tools on hostname first, serial number where available as the tiebreaker.
4. Build the three outputs:
- Coverage gaps: devices in the RMM but absent from EDR/backup/docs views — unprotected or undocumented machines.
- Orphans: devices in exactly one tool — stale records (retired, never removed) or rogue installs. Use last-contact/last-seen to split "stale, propose cleanup" from "active but unenrolled elsewhere, propose enrollment".
- Count matrix: per-tool totals side by side, with deltas and the named devices behind each delta. Call out the billing angle explicitly: which count each tool would bill on, and which direction the MSP is likely over- or under-billing.
5. Sanity checks: devices offline 30+ days in every tool are probably retired — bucket as decommission candidates, not gaps. Devices matched on hostname but with different serials are re-used names, not the same machine.
6. Output the reconciliation with per-source caveats (cap hits, integration absences), the three lists, and recommended actions (enroll, remove stale record, verify with client, adjust billing count). Offer a plain-text summary note (no markdown/emojis).
Guardrails: never present a delta as billing truth without the caveats attached — a capped or stale source invalidates the comparison, and billing disputes are exactly where this report gets used. This skill changes nothing: no removals, no enrollments, no approval actions — cleanup is ticketed work. Hostname matching is heuristic — surface low-confidence matches separately. Name every integration that is NOT enabled so the reader knows which columns are missing, and never infer a tool's inventory from another tool's data.
