# Ranges, Number Formats & Formatting Make targeted edits to the intended cells, preserving unrelated data and layout. Use CLI help or MCP tool descriptions for current command syntax and inputs. This guide explains choices that affect the workbook, not the command catalogue. ## Reusable cell styles Use an existing style when it expresses the requested meaning. A custom cell style can capture a visible source cell's formatting without changing that cell; apply it separately to the intended destinations. Changing a shared custom definition can affect every cell that uses it. Deleting the style removes its name from existing users, with Excel deciding what formatting remains. Built-in definitions are inspectable but not editable through the custom-style lifecycle. Hidden source sheets are not made visible as a workaround. ## Reusable table and dashboard styles Table, PivotTable, slicer, and timeline styles share workbook definitions. Clone a suitable definition when a reusable custom style is requested, then apply it through the owning object's formatting controls. These definitions support less formatting than ordinary cells. An unset element is different from an element with explicit formatting, and Excel can leave native properties unset after a change. Inspect the actual definition before assuming that every requested property has been stored. Custom updates can affect all existing users; deletion can remove their formatting. Neither is a local change to just the selected report. Saving remains explicit, and a native failure does not promise rollback. ## Cell protection Locked cells and hidden formulas are enforced through worksheet protection. Changing those cell flags alone does not protect the sheet. Formula hiding affects Excel's UI, not tool inspection or file encryption; it is not secret storage. See [worksheet protection](/reference/worksheet/#protection-permissions). ## Row and column visibility Visibility changes affect whole intersecting rows or columns, not just the selected cells. Disjoint gaps remain unchanged. Hiding preserves stored dimensions, although native size reads can report zero while hidden. Excel cannot reliably distinguish manual hiding, filtering, zero size, and collapsed groups. Filter and outline information provides context, not proof of the cause. Showing rows does not clear filters or groups; those can hide them again. Protection is not bypassed. ## Protected writes and copies Content writes reject occupied direct destinations unless intentional replacement is authorized. Values, whitespace, zero, false, errors, and formulas displaying empty text are occupied. The same-value replacement is still an overwrite. Formatting alone does not make a truly empty cell occupied. After rejection, correct the destination or clarify unresolved intent. Do not automatically grant overwrite permission, clear conflicting cells, or repeat a confirmation when replacement was already requested. Failed inspection does not establish that a destination is empty. Copy scope can be larger than its starting address: a single-cell destination expands to the source size, and larger destinations repeat the paste. Check the full bounds and the effect of transposing. Copies require unmerged rectangular areas with compatible dimensions. Choose a content-only copy when formatting must remain unchanged. Formula paste can also copy constants and blanks. Formats-only copying preserves content but can transfer protection and conditional rules; validation-only copying preserves content and visual formatting. Skipping empty source cells does not skip formulas that merely display empty text. Value and formula data must match the destination rectangle. Permission to replace contents does not bypass sheet protection. Checks do not predict future spills or Table-generated changes outside the direct destination. Interactive edits remain possible, and a later Excel error can leave partial changes. Copying uses Excel's clipboard; saving remains explicit. ## Number formats and layout Display formatting is not data conversion. A percentage format does not turn 45 into 0.45, and a date format does not convert arbitrary text into dates. Choose units and formats from the column's meaning, not its magnitude. See [report formatting](/reference/report-formatting/) for practical examples. Use US number-format codes. Excel translates display separators for the user's locale; different separators in a screenshot are not necessarily an error. Read-back codes may change literal escaping while keeping the same meaning. Explicit currency symbols remain explicit. Widen columns when values show `#####`, unless a fixed template layout must be preserved. Wrapped text may also need row auto-fit. Heading styles do not necessarily include a colored fill; choose formatting that suits the request. Inspect stored formatting when maintaining a template, and displayed formatting when conditional rules affect appearance. A mixed-style range has no single style: a summary fallback is not proof that every cell uses that style. Use per-cell inspection when the distinction matters. Validation replacement can remove the old rule before Excel rejects the new one. Inspect the resulting rule after failure rather than assuming the previous validation survived. ## Data validation MCP `range_format` action `validate-range` and CLI `rangeformat validate-range` replace the target's existing validation rule. Invalid validation types, comparison operators, and error styles are rejected before removing that rule. This does not promise rollback for errors Excel raises while applying a rule. Explicit `show_input_message: false` / `--show-input-message false` and `show_error_alert: false` / `--show-error-alert false` disable those messages. Omitting these settings uses the documented defaults: input messages off, error alerts on. Blank cells are allowed and list dropdowns are shown by default. Use `get-validation` to inspect the resulting rule and message settings. ## Formulas and merged cells Formula notation and cell-address notation are separate. Relative row/column formulas are interpreted from each destination cell; changing their notation does not change how target addresses are supplied. Write a single merged value at the merged area's top-left cell. A grid write intersecting merged cells can fail; unmerge only when that change is requested, not as an automatic repair to a template. ## Ordinary-range and advanced filtering Use the existing Table's filter when data is already a Table. Ordinary-range filtering applies to an exact header-and-data rectangle and does not silently replace a different filter elsewhere on the sheet. Excel can normalize selected values into comparisons or combined criteria. Read the actual criteria and visible rows rather than comparing the request's original spelling with readback. Clearing ordinary criteria retains dropdowns. Advanced filtering uses worksheet criteria and can filter in place or copy results. Copied-output protection checks can cover more rows than ultimately match. Excel does not expose the original advanced-filter criteria for faithful readback. Clearing that state can affect worksheet-wide row filtering, so authorize it explicitly rather than silently replacing it with an ordinary filter. ## Native data cleanup Choose duplicate keys and header handling deliberately. Duplicate removal keeps the first record for those keys, including blank records, and clears removed rows within the selection rather than shifting cells below it. For text-to-columns, protect identifiers, leading zeros, and dates from unwanted conversion. Excel parses source formula text, not calculated formula results. Check the full output area, including empty fields. Parsing in place can replace the source; a separate output can overwrite neighboring data and needs permission where occupied. Preflight uses a short-lived, unsaved calculation workbook containing the requested data, not a saved recovery copy. Native failures do not promise rollback or bypass protection. ## Native fill and series Copying a source edge and extending a pattern are different tasks. Pattern extension includes the source and grows in one direction on the same sheet. Formats-only extension preserves contents. Trend fitting can change source values, so treat it as an intentional replacement. Series safety checks can cover the whole possible destination even if Excel stops early. Inspect the generated values rather than assuming a successful call establishes the intended pattern. ## Native formula relationships Native relationship inspection is not a complete workbook dependency graph. It can omit cross-sheet and external references, miss dynamic references, or report only an anchor rather than the effective target. An empty relationship list does not prove that a cell has no dependencies. Use the reported coverage and unresolved lookups. Inspection does not parse formulas to invent missing links, recalculate, open external workbooks, select cells, or create tracing arrows. ## Calculation and merged cells Calculate and read back results when the task depends on newly written formulas. Writes attempt to restore the previous calculation mode, but restoration can fail without failing the write. See [calculation guidance](/reference/calculation/). Newer formula support depends on the Excel session. Using a legacy formula API does not add modern functions to an older Excel installation, and failures are not repaired by blindly retrying another notation. Read cell-error details when formulas fail. Excel cannot always identify the exact broken sub-reference. Spill inspection reflects current calculated state; a blocked spill has no established intended output extent. Do not infer that extent from an error or claim fresh results without calculation. ## Clearing ranges Choose whether to remove contents, formats, or both. Clearing has no tool-level undo. Discarding unsaved changes can reverse in-memory edits, but also loses earlier unsaved work; it is not targeted undo. ## Finding matches Choose text search for matching text and cell-category discovery for formulas, errors, truly blank cells, or visible cells. Formulas displaying empty text are not blanks, and visible-cell discovery excludes hidden rows and columns. Search can return only part of its cell details while still reporting the exact total. Check truncation before calling a list complete. Limiting returned details does not limit the work required to count all matches. ## Links, comments, and names Removing a hyperlink preserves its cell content. Internal links depend on real sheet names and cell references. Threaded comments require a supporting desktop Excel version. Local text and replies are not Microsoft 365 mentions, assignments, reactions, sharing, or coauthoring state. Named ranges refer to cells. Define the reference before writing its value. Discovery omits internal/hidden names and can omit large value previews; read the intended name when values are needed. Changing a query parameter does not itself refresh its load. ## Dates and reference spelling Excel date serials are not Unix timestamps or Python ordinals. Check the workbook's date system before external conversion, including the historical 1900 leap-year exception. Prefer display formatting when only readable dates are needed. Use actual worksheet names. In an Excel formula reference, a name with spaces uses `'Sales Data'!A1`, not backticks.