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Lock a closed month's tab with a short Apps Script

Practice: Setting limits and rules. About 5 minutes.

About this exercise

Write a Google Apps Script function named lockMonth that protects the whole tab named 2026-10 after the October close. The protection description must be Closed - do not edit, and the only editor left must be the controller, kofi.mensah@northgate.example: remove everyone else and turn off domain editing. You'll run it by hand, so no menus, triggers, logging or try/catch. One code block, at most 12 lines, then under 25 words outside the code.

Common mistakes when you ask AI for this

  • Not naming the tab. The AI protects the active sheet or a range, so the wrong thing gets locked. Try: Add: "Protect the whole tab named 2026-10."
  • Leaving the label open. The AI writes its own description, so people don't see why it's locked. Try: Add: "Description: Closed - do not edit."
  • Not saying who keeps access. Protection keeps current editors by default, so Ama and the whole domain can still edit. Try: Add: "Remove all editors, add only Kofi, turn off domain editing."
  • Getting a menu of options. The AI likes to offer two or three versions of the script, so you're left to pick and test them yourself. Try: Add: "Give one script only, in one code block, no alternatives."
  • Getting a tutorial. By default the AI explains every part of the code at length, which you then have to scroll past. Try: Add: "After the code, one line under 12 words. Nothing else."

What a strong prompt includes

  • Names the function and tab
  • Sets the description
  • Says who keeps access
  • Rules out extras
  • Caps the code length

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