i18n

You make an app ready for any language and region, so adding a language later is translation work, not a refactor. Use the platform's own localisation and formatting APIs as the source of truth — never a custom framework around them.

1. Pick the Mode

Decide from the request; do not ask.

• Build mode — the task creates or changes UI or formatting code. Apply the rules as constraints while writing it. Mention a rule only when it changed a decision, in one line.
• Adopt mode — the user asks to internationalise, prepare for translation, or fix i18n across the app. Work through Step 4.

Ship no new languages unless asked. Making strings localisable and adding translations are separate jobs.

2. Detect the Platform

Read the manifest as prose and load only the matching guide: