Skip to main contentData Operations
X21 exposes a suite of tools for reading and writing worksheet data with precision. Each tool corresponds to a handler inside the Excel API service and is orchestrated by the Deno backend.
Reading Data
read_values – Retrieves cell values (and formulas) for a specific range. Responses include:
values – 2D array mirroring the requested range.
formulas – Optional formula text when available.
address – Range address for auditing.
read_format – Gathers formatting attributes (font, colour, alignment, number formats, borders). Powered by FormatManager and per-attribute readers such as BoldFormatReader.
- Usage Tips
- Provide explicit
workbookName, worksheet, and range to avoid ambiguity.
- Use wildcards like entire columns (
A:A) or rows (3:3) when reading large sections—ExcelSelection can handle them efficiently.
Writing Data
write_values – Writes tabular data using a 2D array. Key behaviours:
- Dimensions must match the target range; the tool validates before writing.
- Supports formulas (e.g.,
=SUM(A2:A10)). Use relative references for patterns, absolute references for constants.
- Returns
oldValues and newValues so changes can be inspected or reverted.
write_format – Applies styling across a range. Payloads can include:
- Font properties (
bold, italic, fontSize, fontName).
- Colours (hex strings or RGB).
- Borders, alignment, number formats.
- The backend optimises changes using
FormatWriter to reduce redundant operations.
Best Practices
- Batch large updates into a single tool call to reduce Excel automation overhead.
- For append operations, combine
read_values to find the next empty row with write_values to insert data.
- When altering formats, explicitly include only the properties you want to change; the formatter leaves unspecified attributes untouched.
- Use View mode to preview writes before approving. Revert data is generated automatically, enabling quick rollbacks if the outcome isn’t correct.
Error Handling
- Invalid ranges or protected sheets trigger detailed error messages from the Excel API. The tool reports them back to the UI as
tool:error.
- If the workbook changes while a tool is pending (e.g., the user edits cells manually), re-run
read_values to ensure the latest context before approving writes.
These data operation tools cover most day-to-day automation tasks, from summarising datasets to injecting formulas generated by Claude.