calendar-month-names

name	calendar-month-names
description	Use user-provided month names or labels in calendar implementations and output. Use when implementing or updating a calendar and the user has given a list of month names (including for leap months), so the implementation does not default to numeric-only output.

Calendar Month Names

When to use this skill

Use this skill when:

• Implementing a new calendar or timekeeping system and the user provides month names (in any form: transliterations, native script, cuneiform, etc.).
• Updating an existing calendar and the user adds or corrects month names.
• The spec or user message includes an ordered list of months; do not ignore it in favor of "month 1", "month 2", or numeric-only output.

Use the names the user provided

1. Include the names in the implementation

   • Define a month-names array (or equivalent) using the exact labels the user gave, in the order they gave.
   • Use these names in the calendar’s formatted output (the string or object returned to the UI), not only in comments or docs.
   • Use literal characters only: Paste the user’s month names (native script, cuneiform, etc.) directly into the source as literal text. Do not use Unicode escape sequences (\uXXXX, \u{XXXXX}, or similar) for month names — they are error-prone, hard to read, and often wrong (e.g. 4-digit \u cannot represent code points above U+FFFF). Literal characters in the source are correct, verifiable, and match what the user provided.

2. Order is usually sequential

   • The user’s list is typically in calendar order (month 1, month 2, …).
   • Map your internal month index (1–12 or 1–13 with leap) to the correct name by position.

3. Leap months need interpretation

   • Leap months are often not a separate entry in the list; they repeat or extend an existing month’s name.
   • Common patterns:
     • Repeated name: e.g. "Addaru II", "Ululu II", or "month 12 (leap)" — the leap month shares the number/name of the month it follows.
     • Single leap entry: the user may list one leap name (e.g. "𒌚𒋛𒀀𒆥") that appears only in a specific cycle position (e.g. year 17); other years use a different leap name (e.g. "𒌚𒋛𒀀𒊺").
     • Skipped in list: the main list might have 12 names; the 13th "month" in a leap year uses the same name as the repeated month (e.g. second Addaru).
   • Follow the user’s wording: if they say "leap month after month 6" or "Addaru II at the end", implement that; do not invent a different rule.

4. Do not default to numbers only

   • If the user provided names, the primary output should use those names (possibly with a numeric or "leap" qualifier).
   • Numeric fallback (e.g. "month 6 (leap)") is acceptable only when no names were given or for debugging; when names exist, show them.

Do not use Unicode escapes for month names

• Never encode month names (or any user-provided labels) with \uXXXX or \u{XXXXX} in JavaScript.
• Always paste the actual characters (e.g. 𒌚𒁈, 甲, 正月) into the source so the labels are literal strings.
• This avoids wrong glyphs (e.g. \u13048 parsed as \u1304 + "8"), keeps code readable, and matches the user’s list exactly.

Quick checklist

• Month names from the user’s list are stored in code in the same order.
• Names are literal characters in the source; no \u or \u{...} escapes for month labels.
• Formatted calendar output uses those names (or the correct repeated name for leap months).
• Leap-month placement and naming match the user’s description (which month is repeated, and where).
• No numeric-only output when the user supplied names.