A spreadsheet migration changes totals without warning

The problem

A workbook can open successfully while formulas, dates or unsupported features behave differently.

Agent job

Inventory formula and feature differences; build invariant checks for key totals; compare sample outputs; deliver an exception report and proposed repair patch on copies.

Expected output

Migration QA workbook, formula-difference inventory and reproducible acceptance checks.

Why an agent / simpler alternative

Assessment

The agent can inspect formulas, explain unsupported features and design checks based on business meaning. Deterministic recalculation and comparisons establish actual behavior. Built-in compatibility tools should be tried first, and a human needs the real destination app to validate the result.

Setup requirements

Items

1. Untouched source and destination copies with exact application/version details

2. Owner-defined invariants and non-financial business purpose

3. Actual destination spreadsheet application, not just a file parser

4. Synthetic edge-case inputs; macros, live connectors and regulated models excluded

Inputs and access

1. Name

   Source workbook copy and destination export

   Source or owner

   Prospective consenting customer or specified official publisher

   Sensitivity

   Use synthetic, public or appropriately deidentified material; confirm actual sensitivity before work

   Permission needed

   Owner authorizes scoped access and processing; verify rights and retention before receiving files

2. Name

   Owner-defined control totals

   Source or owner

   Prospective consenting customer or specified official publisher

   Sensitivity

   Use synthetic, public or appropriately deidentified material; confirm actual sensitivity before work

   Permission needed

   Owner authorizes scoped access and processing; verify rights and retention before receiving files

3. Name

   Synthetic edge-case inputs and version details

   Source or owner

   Prospective consenting customer or specified official publisher

   Sensitivity

   Use synthetic, public or appropriately deidentified material; confirm actual sensitivity before work

   Permission needed

   Owner authorizes scoped access and processing; verify rights and retention before receiving files

Proposed steps

1. 1

   Inventory workbook tabs, formulas, formats and external dependencies; record both app versions.

   Expected output: Migration feature manifest

   Approval gate: Reject excluded macros, live links or regulated-use models from the base scope.

2. 2

   Agree control totals and edge cases that express the workbook’s intended business behavior.

   Expected output: Acceptance-check register

   Approval gate: Owner confirms expected outputs; the agent cannot invent the business rule.

3. 3

   Run built-in compatibility checks and inspect formula/date/format differences on copies.

   Expected output: Compatibility and formula-difference report

   Approval gate: Do not overwrite the source or execute unknown macros.

4. 4

   Recalculate both copies in their actual applications using the same approved fixture inputs.

   Expected output: Recalculation evidence and result table

   Approval gate: If the destination app is unavailable, mark the test incomplete.

5. 5

   Investigate mismatches and propose narrowly scoped repairs with before/after evidence.

   Expected output: Repair proposals and unresolved exceptions

   Approval gate: Owner approves each semantic change before applying it to a copy.

6. 6

   Rerun all agreed invariants and hand over checked copies and remaining limitations.

   Expected output: Migration acceptance report

   Approval gate: Human signs off destination behavior before operational use.

Synthetic output illustration — not an executed result

Synthetic

Yes

Executed

No

Text

SYNTHETIC: Check INV-03: source reorder total 47, destination 52. Difference caused by ambiguous date 03/04/2026 after locale conversion. Status: BLOCKED pending date-rule decision. These numbers are illustrative, not recalculation results.

Human approval boundaries

1. Workbook owner approves checks and all repair changes; human accepts destination behavior. Exclude accounting, tax or regulated decision models.

2. Human service provider reviews quality, scope and quoted fee; customer approves contract, delivery recipients and payment terms. Separately approve purchases, credentials, publication and external sends. No commitments or payments are made in this research.

Failure modes

1. Cached values hide broken recalculation

2. Date systems and locale change meaning

3. External links may be unavailable

4. Macros are outside the base scope

Recovery and troubleshooting

Items

1. If only cached values are available, stop and request real recalculation; do not equate a readable file with correctness.

2. If locale changes date interpretation, obtain an explicit date rule and test boundary examples before conversion.

3. If a repair changes unrelated totals, revert the copy and isolate the cause before retrying.

Unexecuted validation plan

Sample setup

Create a three-tab inventory-planning fixture with locale dates, missing values and one unsupported formula.

Acceptance checks

1. Recalculate in the actual destination before acceptance

2. All agreed totals match or have approved explanations

3. No original overwritten

4. Owner verifies at least five edge cases

Stop conditions

1. Stop if data authority or rights are unclear.

2. Stop if critical seeded failures are missed; do not claim readiness.

3. Stop if manual correction time exceeds the pilot effort budget without customer approval.

Executed

No

Costs and effort — unknown or hypothetical

Status

unknown_or_estimate

Currency

CAD

Items

1. Agent subscription/API usage: not quoted; verify current plan and commercial data terms.

2. Human intake, rights review, QA and revisions: unknown until timed pilot.

3. Storage, hosting, integration and payment-processing costs: excluded unless separately agreed.

4. Customer acquisition and support time: not measured.

Caveat

No margin or income estimate. Price hypotheses are editorial offer tests, not observed market rates; taxes, scope and effort require a real quote.

Proposed service concept — earnings not verified or guaranteed

Buyer

Small operations team moving an owned workbook between spreadsheet versions or platforms

Deliverable

Migration QA workbook, formula-difference inventory and reproducible acceptance checks.

Charging basis

Fixed-scope workbook acceptance-test service; additional versions or repairs quoted separately.

Acquisition channel

Permission-based discovery with existing professional contacts, referrals or an opt-in sample page; none executed.

Assumptions

1. Customer has this unresolved problem and values a reviewed deliverable above existing built-in alternatives.

2. A consenting pilot confirms data access, achievable quality and economically tolerable review time.

3. Provider can deliver within a written scope and supports the result.

Revenue guarantee

No

Canadian adaptation — proposed

Proposed Canadian pilot: test actual English/French spreadsheet locale, decimal/list separators, ambiguous date formats and CAD/USD labels without automatic conversions. Use the actual destination version and owner-defined units. No financial/tax model certification or completed Canadian test.

Limits

1. Original proposed plan; untested.

2. Problem and capability references are evidence of context only, not demonstrated end-to-end success, customer demand, willingness to pay or profitability.

3. Compatibility, workload, delivery effort and availability must be verified in a real authorized pilot.

4. Agent-generated checks cannot establish spreadsheet equivalence without actual recalculation in the destination app; a human must provide that environment.

5. Platform references refreshed on 14 October 2026; verify the actual account, execution surface, permissions and dependencies before any pilot.

Candidate platforms — compatibility untested

1. Name

   Codex

   Required capabilities

   1. File analysis, code execution and test/report artifact creation.

   Capability source urls

   1. https://learn.chatgpt.com/docs/codex/cli

   2. https://learn.chatgpt.com/docs/artifacts-viewer

   3. https://learn.chatgpt.com/docs/sandboxing

   Workflow compatibility

   Unknown; verify in the proposed first test.

   Historical candidate name

   Codex

   Selection basis

   Editorial candidate from general capabilities; exact end-to-end fit untested.