Summary

Adds a new addConditionalFormatting tool that appends a BooleanRule conditional format rule to one or more ranges in a spreadsheet via batchUpdate.

What's supported

Condition types:

• NUMBER_GREATER, NUMBER_GREATER_THAN_EQ, NUMBER_LESS, NUMBER_LESS_THAN_EQ — single value comparisons (e.g. conditionValues: ["40"])
• NUMBER_EQ, NUMBER_NOT_EQ — equality comparisons
• NUMBER_BETWEEN, NUMBER_NOT_BETWEEN — requires exactly two values (lower bound first)
• BLANK, NOT_BLANK — no condition values
• CUSTOM_FORMULA — arbitrary formula string (e.g. "=$A1>$B1")

Format options: backgroundColor (hex), bold, italic, strikethrough, underline, foregroundColor (hex), fontSize

Other: sheetName (optional, defaults to first sheet), ranges (array of A1 notation strings, min 1)

What's not supported

• GradientRule — the Sheets API has a separate GradientRule type for continuous color scales (min/mid/max). This tool only implements BooleanRule. GradientRule would be a separate tool.
• Updating existing rules — each call appends a new rule. Use deleteConditionalFormatting (not yet implemented) to remove rules before re-adding.
• Text-based conditions — TEXT_CONTAINS, TEXT_NOT_CONTAINS, TEXT_STARTS_WITH, TEXT_ENDS_WITH, TEXT_EQ are valid Sheets API condition types but not exposed here. Can be added if needed.
• Date conditions — DATE_EQ, DATE_BEFORE, DATE_AFTER, etc. — not currently exposed.

Validation

Zod .refine() validates that the correct number of conditionValues is provided per condition type:

• 0 values for BLANK / NOT_BLANK
• 2 values for NUMBER_BETWEEN / NUMBER_NOT_BETWEEN
• 1 value for all other types
• At least one format option must be specified

Implementation notes

• Logic delegated to a new addConditionalFormatRule helper in googleSheetsApiHelpers.ts
• Follows the same pattern as formatCells and other formatting tools
• Uses parseA1ToGridRange to convert A1 notation to Schema$GridRange objects

Test plan

• Apply a NUMBER_GREATER rule with backgroundColor — verify cells exceeding threshold turn the expected color
• Apply a CUSTOM_FORMULA rule — verify formula-based highlighting works
• Apply a BLANK rule (no conditionValues) — verify it doesn't reject the call
• Apply a NUMBER_BETWEEN rule with two values — verify range highlighting works
• Confirm Zod validation rejects mismatched conditionValues counts
• Confirm at least one format option is required (Zod refine)

🤖 Generated with Claude Code