Excel Exploration Skill

You can interact with open Microsoft Excel workbooks using the xl.exe CLI tool. This enables spreadsheet exploration, formula analysis, and data modification through natural conversation.

Session Workflow

1. Start by Listing Workbooks

Always begin by showing the user what workbooks are available:

"${CLAUDE_PLUGIN_ROOT}/bin/xl.exe" list

This returns JSON with all open Excel instances and workbooks. Each workbook has a target_id you'll use for subsequent commands.

2. Help User Select a Workbook

Present the workbooks in a readable format. Include:

• Workbook name and path
• Whether it has unsaved changes
• Which one is active (if multiple)

Even if only one workbook is open, show it and confirm with the user before proceeding.

3. Explore the Workbook

Once a target is selected, gather context:

• List sheets: xl.exe sheet list --target <id>
• List named ranges: xl.exe name list --target <id>
• Read specific ranges as needed

4. Respond to User Requests

Use the appropriate commands based on what the user wants to do. For modifications, always use --mode rw.

Command Reference

Listing and Discovery

List all open workbooks:

xl.exe list

List sheets in a workbook:

xl.exe sheet list --target <target_id>

List named ranges:

xl.exe name list --target <target_id>

Get named range details:

xl.exe name get --target <target_id> --name <name>

Reading Data

Read a range:

xl.exe range read --target <target_id> --sheet <sheet_name> --a1 <range>

Example:

xl.exe range read --target "excel:1234:0x000A1234:wb:0" --sheet Sheet1 --a1 A1:D10

The output includes:

• values: 2D array of cell values
• formulas: 2D array of formulas (null for non-formula cells)
• types: Cell types (number, string, boolean, date_serial, error, null)

Modifying Data (requires --mode rw)

Write values to a range:

echo '{"values": [[1, 2], [3, 4]]}' | xl.exe range write --mode rw --target <target_id> --sheet <sheet_name> --a1 <range>

Write formulas:

echo '{"formulas": [["=SUM(A1:A10)"], ["=AVERAGE(B1:B10)"]]}' | xl.exe range write --mode rw --target <target_id> --sheet <sheet_name> --a1 <range>

Add a sheet:

xl.exe sheet add --mode rw --target <target_id> --sheet <new_sheet_name>

Rename a sheet:

xl.exe sheet rename --mode rw --target <target_id> --sheet <old_name> --new-name <new_name>

Delete a sheet:

xl.exe sheet delete --mode rw --target <target_id> --sheet <sheet_name>

Add a named range:

xl.exe name add --mode rw --target <target_id> --name <name> --refers-to "=Sheet1!\$A\$1:\$C\$10"

Delete a named range:

xl.exe name delete --mode rw --target <target_id> --name <name>

Save the workbook:

xl.exe workbook save --mode rw --target <target_id>

Calculation Control

Check calculation mode:

xl.exe calc status --target <target_id>

Trigger calculation:

xl.exe calc run --mode rw --target <target_id>

Set calculation mode:

xl.exe calc set --mode rw --target <target_id> --calc-mode manual
# Options: manual, automatic, automatic_except_tables

Safety Guidelines

Read-Only Mode (Default)

By default, all commands run in --mode ro (read-only). This guarantees:

• No writes to values, formulas, formats, or structure
• No calculation triggers
• No refresh of external data connections
• No opening or closing workbooks

Read-Write Mode

Use --mode rw only when the user explicitly requests a modification. Always:

1. Confirm the intended change with the user
2. Report what was modified after the operation
3. Remind user to save if they want to keep changes

Error Handling

Commands return JSON with "ok": true on success or "ok": false with error details:

• NO_EXCEL_INSTANCE: No Excel processes running
• WORKBOOK_NOT_OPEN: Target workbook no longer open
• SHEET_NOT_FOUND: Sheet name doesn't exist
• RANGE_INVALID: Invalid A1 reference
• MODE_VIOLATION: Attempted write in read-only mode

Output Interpretation

Cell Values

• Numbers are returned as JSON numbers
• Strings are returned as JSON strings
• Booleans are true/false
• Empty cells are null
• Dates are Excel serial numbers (days since 1899-12-30)

Formulas

• Formulas include the leading =
• Cells without formulas show null in the formulas array
• Named range references in refers_to use the format =Sheet!$A$1:$B$10

Example User Prompts

Users might ask things like:

Exploration:

• "Show me what workbooks are open"
• "What sheets are in this workbook?"
• "Read the data in A1:D10"
• "What's in the Summary sheet?"
• "What named ranges are defined?"
• "Show me the formulas in column B"

Analysis:

• "Find cells that reference Sheet2"
• "What formula is in cell C5?"
• "Show me all cells with SUM formulas"
• "Are there any circular references?"

Modification:

• "Add a new sheet called Results"
• "Rename Sheet1 to RawData"
• "Create a named range called SalesTotal for B2:B100"
• "Write these values to A1:C3"
• "Update the formula in D5 to use the new named range"

Refactoring:

• "Replace hardcoded references with named ranges"
• "Consolidate duplicate formulas"
• "Standardize the sheet naming"

When handling these requests, break down complex tasks into steps, show the user what you find, and confirm before making changes.