Field report · FR.01 · FP&A FORECAST AUTOMATION · FORTUNE-500 MARKETPLACE

The forecast lived in one spreadsheet. Now it runs as a system.

A Fortune-500 marketplace ran a revenue-driver forecast for 25 countries out of a single workbook: 16 sheets, 9,489 formula cells, and a lot of copy-paste. We rebuilt it as a governed agentic cycle. The math stayed deterministic. The judgment stayed human. The two days became five hours.

Client details generalized to protect confidentiality · figures from the engagement's technical brief

2d → 5h
Forecast cycle time
9,489
Formula cells mapped
0
Copy-paste steps remaining
100%
Writes tied to an approval

The situation · 01

Excel was the integration layer.

Every cycle, an analyst hand-pulled data from three platforms (the planning system, the data warehouse, and shared sheets): manual queries, connector refreshes, file exports, values typed into the grid.

The workbook did everything: integration, calculation, and control. Outliers were caught by eye. Publication was a manual upload, re-downloaded and compared until it tied out, about three passes per cycle as targets and FX rates moved.

Nothing was versioned. Replaying a past cycle, or explaining a number to an auditor, meant archaeology.

Anatomy of the old cycle

M.01Manual queries against the warehouse
M.02Connector refreshes and file exports
M.03Copy-paste between four systems
M.04Values typed directly into the grid
M.05Visual checks as the only error gate
M.06Manual upload, re-download, reconcile, repeat

Errors surfaced after calculation and publication · rework returned to the workbook · ~3 passes per cycle

The design decision · 02

Code calculates. The agent explains. People decide.

The most important decision was what the agent would not do: forecast. Judgment, not math.

01 · CODE

Deterministic core

Versioned code executes every calculation the workbook used to hold: mix, rate, FX, weighting, cascade, true-up, reconciliation. Same inputs, same outputs, every time.

02 · AGENT

Assisted review

The agent coordinates the cycle, explains connector and data-quality findings, writes the variance narrative, and triages anomalies, the work that used to be eyeballing.

03 · HUMAN

Owned decisions

Analysts set assumptions, resolve exceptions, and approve every write to the planning system. Three gates, none of them optional.

No partial-input runs

A stale or failed source stops the cycle before the model executes. Never a forecast built on half a snapshot.

One immutable cycle ID

Inputs, assumptions, approvals, overrides, and outputs stay reconstructable. Any past cycle can be replayed.

Signed write package

Only the exact validated version can obtain scoped write access to the planning system.

The new cycle · 03 · 05 PHASES · 03 GATES

Pull. Run. Check. Write. Prove.

Each phase produces evidence, not just a spreadsheet. The cycle advances only when its exit conditions are met.

PHASE 01 < 30 min

Pull

Connector jobs assemble a complete, versioned input snapshot; shape and freshness are validated before anything runs.

Gate 1 · analysts confirm assumptions

PHASE 02 < 45 min

Run

The deterministic model executes the full calculation chain as a versioned run: 25 countries, weekly splits.

PHASE 03 < 30 min

Check

Automated benchmarks flag outliers; the agent explains each finding so analysts resolve, correct, or override.

Gate 2 · analysts authorize the write

PHASE 04 < 10 min

Write

The signed, validated package publishes to the planning system through scoped credentials. Nothing else can.

PHASE 05 < 10 min

Prove

Post-upload reconciliation confirms the live numbers tie out before anyone downstream is notified.

Gate 3 · analysts accept and release

Exceptions are durable, resumable states: a failed source or unresolved anomaly pauses the cycle; it never limps forward on partial work

What the team keeps · 04

Same judgment. A fraction of the cycle.

The analysts still own every number that matters: assumptions, exceptions, and the decision to publish. What they no longer own is the plumbing: the queries, the copy-paste, the eyeball checks, the upload-reconcile loop.

Every cycle now leaves behind an evidence package an auditor can walk through: what went in, who approved what, and proof the published numbers tie out.

Delivery shape

Implementation engineers2
Delivery increments · working path, expand, harden3
Release path12–14 wks
Definitions locked with the client before build7

The first increment shipped a thin, working end-to-end path, not a framework. Capability came second, production hardening third.

Sound familiar? · THE PATTERN

Most companies have a workbook like this.

A spreadsheet that quietly became the integration layer for a process the business depends on: maintained by one person, checked by eye, impossible to replay.

The fix is rarely "more AI." It is a governed cycle: deterministic code for the math, an agent for the explanation and triage, and your people at the gates.

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