Variance commentary
Given current-period actuals, prior-period actuals, and budget for the same scope, produce a commentary table.
Threshold
Flag a line for commentary if either is true:
- Absolute variance ≥ the firm's materiality threshold (use the provided value; default 5% of the line or a fixed floor, whichever is greater)
- The line is on the "always comment" list (revenue, headcount cost, cash)
For each flagged line
A driver explains why, not what: "Cloud spend up $1.2M on incremental GPU reservations for the May launch" — not "Cloud spend increased $1.2M (18%)."
Sourcing the driver
Look at the activity behind the line (journal-source breakdown, vendor mix, headcount delta, volume × rate) via the internal-gl MCP. If the driver isn't clear from the data, write "driver unclear — flag for controller" rather than inventing one.
Output
The commentary table plus a short narrative (3–5 sentences) summarizing the period's biggest movers.