> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vortexiq.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Header Schema Drift, Google Sheets KPI card, Vortex IQ Nerve Centre

> Diff of the header row (row 1 of the range) against the last-known-good header signature. Catches renamed/reordered/deleted columns the importer depends on. Requires historical seed of the baseline header.

**[Nerve Centre KPIs](/nerve-centre/kpi-cards/google-sheets) · [Audit Profile](/nerve-centre/kpi-cards/google-sheets/audit) · [Sentiment Settings](/nerve-centre/kpi-cards/google-sheets/sentiment)**

## At a glance

* **Category:** Freshness & Integrity
* **Type:** Key Metrics
* **Chart:** alert\_list
* **Format:** number
* **Time window:** RT/vsP
* **Alert trigger:** header signature != last-known-good

## Calculation

Diff of the header row (row 1 of the range) against the last-known-good header signature. Catches renamed/reordered/deleted columns the importer depends on. Requires historical seed of the baseline header.

## Known limitations

*Known limitations, FAQs, or reconciliation notes specific to this card. Replace this block when authored.*