workflow-xlsx-formula-cells

# Excel Formula Cell Conventions ## What this skill covers How to render formula intent and cross-sheet dependencies in markdown-tabular output so a recipient can reconstruct a working Excel model by replacing the textual formula column with cell-relative Excel formulas. **Prerequisite**: the layout conventions in `workflow-xlsx-tabular-conventions` (header row, units row, source column) must already be applied before adding formula columns. ## Formula column ### Purpose The `Formula` column communicates the computational intent of each row. It is **descriptive text**, not an executable formula. The canonical numeric value computed by corp-finance-mcp tools appears in the data column alongside it. The recipient uses the formula text as a guide when rebuilding cell-relative Excel formulas. ### Format The formula text uses human-readable Excel notation: - Reference cells by their row label, not by coordinates: `=Revenue * Margin` not `=B5 * C5` - Reference prior-period cells with a terse modifier: `=Prior * (1 + g)` for compounding - Reference assumption cells by their label: `=WACC` (the recipient resolves this via the named-range substitute — see `workflow-xlsx-named-ranges`) - Reference cross-sheet values with the `->` arrow: `=->Assumptions!WACC` ### Example ``` | Item | FY2025 | FY2026 | FY2027 | Formula | Source | |------------------|--------|--------|--------|------------------------|-------------------| | Revenue | 100.0 | 115.0 | 132.3 | =Prior * (1 + g) | assumption: g=15% | | EBITDA | 25.0 | 28.8 | 33.1 | =Revenue * margin | derived | | EBITDA Margin | 25.0% | 25.0% | 25.0% | =->Assumptions!margin | ->Assumptions | | D&A | (5.0) | (5.8) | (6.6) | =Revenue * da_rate | assumption | | EBIT | 20.0 | 23.0 | 26.5 | =EBITDA - D&A | derived | | Discount Factor | 0.917 | 0.841 | 0.772 | =1 / (1 + WACC)^n | ->Assumptions!WACC| | PV of FCFF | 18.3 | 19.3 | 20.5 | =FCFF * Discount Factor| derived | ``` ### When to include the formula column Include the `Formula` column when: - The recipient is expected to rebuild a formula model in Excel (not just read the output) - The deliverable is a schedule with mathematical relationships (DCF FCFF, debt amortisation, three-statement, returns) - The derivation from assumptions is non-trivial and the mapping is not obvious Omit the `Formula` column for: - Pure data tables (comp sets, trade lists, market data extracts) - Single-computation outputs where the tool reference in the `Source` column is sufficient ## Cross-reference convention ### Syntax Use the literal arrow `->` and bang `!` separator to denote cross-sheet references: ``` ->SheetName!ColumnLabel ``` Example values in the `Source` column: - `->Assumptions!WACC` — value comes from the WACC row in the Assumptions sheet - `->DebtSchedule!TotalDebt_FY2026` — value comes from a row in the Debt Schedule sheet ### In the Formula column When a formula's input comes from another sheet: ``` | WACC | 9.5% | =->Assumptions!WACC | ->Assumptions!WACC | ``` The formula text makes the cross-sheet dependency explicit so the recipient knows where to pull the linked cell from. ### Heading anchor form When the target is a heading anchor (not a row label that appears as a cell): ``` ->Assumptions#assumptions-wacc ``` The `#` separator denotes a markdown heading anchor (see `workflow-xlsx-named-ranges`). Use this form when the target is a named block rather than a single-row value. ## Workbook cross-sheet reference map For large multi-sheet deliverables, include a reference map at the end of the document: ``` ## Cross-Reference Map | From Sheet | Label | To Sheet | Anchor | |-----------|-------|---------|--------| | FCFF Schedule | WACC | Assumptions | #assumptions-wacc | | Debt Schedule | Terminal EBITDA | Operating Model | #op-model-terminal | | Returns | Exit Equity | Debt Schedule | #debt-schedule-exit | ``` This map allows a post-paste automation script to resolve `->` references into cell coordinates. ## Quality gates - [ ] Formula column present on all schedule sheets where the recipient is expected to rebuild the model - [ ] Formula text uses label references, not coordinate references (e.g., `=Revenue * margin` not `=B5 * C5`) - [ ] Cross-sheet references use `->SheetName!Label` syntax consistently - [ ] Canonical numeric value from corp-finance-mcp appears in the data column alongside formula text - [ ] Formula column omitted for pure data tables (comp sets, market data) - [ ] Cross-reference map included for deliverables with more than 2 sheets ## Related skills - `workflow-xlsx-tabular-conventions` — prerequisite: header row, units row, source column layout - `workflow-xlsx-named-ranges` — heading anchor substitutes for Excel named ranges - `workflow-xlsx-workbook-writer` — `office_xlsx_write` MCP tool; the `formulas` array parameter accepts actual Excel formula strings to inject after paste