Chatto i18n Hygiene

Keep Chatto messages complete, consistent, and correct at their call sites. Scope this workflow to apps/frontend/. Authling and Runling are independent products. Inspect packages/translatto/ only when a finding concerns the shared runtime; keep Chatto policy out of that package.

Establish scope

Read apps/frontend/AGENTS.md, especially Internationalization, and docs/adr/ADR-065-runtime-json-client-internationalization.md. Use docs/GLOSSARY.md for product terms. Follow the frontend-review and Svelte skills when reviewing components.

Use the user's requested scope. With no narrower scope, check all catalogs and scan production frontend source. State which surfaces received manual review. An audit request is read-only. A cleanup request permits focused fixes to confirmed defects; do not rewrite translations merely for style.

Run existing checks

From the repository root:

mise x -- pnpm --filter chatto-frontend exec vitest run --project server src/lib/i18n

Read the tests before interpreting their results. catalogs.spec.ts checks literal message keys, complete catalog structure, placeholders, regional overlays, copied multi-word English, and functional examples. Other tests in this directory cover locale selection, direction, loading, and message output. Passing checks do not prove translation quality or complete call-site coverage.

Inspect catalogs

• Derive the base locale, selectable locales, and sparse overlays from src/lib/i18n/locales.ts; do not infer completeness from a regional tag.
• Check every JSON file under apps/frontend/messages/ for empty values and duplicate object keys. Ordinary JSON parsing silently discards duplicate keys. Preserve catalog structure and placeholder names and multiplicity.
• Compare sparse overrides with their configured fallback. Report redundant overrides, and check missing regional spelling differences. Do not fill a sparse overlay with a copy of its fallback.
• Inspect copied one-word English and all plural branches as well as messages covered by tests. Brand names, protocol tokens, and valid shared terms can be identical. Add an identicalTranslations.ts exception only when the text is correct for that key and locale; never use exceptions to hide missing work.
• Follow the form of address in the frontend instructions. Check German du/dein, Swiss spelling, British source spelling, and US overrides. Keep functional tokens such as DELETE and syntax examples valid.
• Check plural categories against the target language, not English's branch set. Preserve other and numeric count arguments. Use complete messages with placeholders instead of concatenating translated fragments.

Inspect production call sites

Use rg to find candidates, then read their context. Exclude fixture text, stories, test harnesses, documentation examples, logs, user content, and deliberately literal identifiers before reporting untranslated copy.

Check visible text, accessibility names, tooltips, placeholders, validation, toasts, empty states, errors, and confirmation dialogs. Trace dynamic keys and aliases: the literal-key test cannot prove that each runtime key exists. Do not delete apparently unused keys until dynamic callers are ruled out.

Check that locale changes update rendered labels, dates, numbers, and lists. Look for fixed locales, early translation snapshots, and locale-independent formatting of user-visible values. Preserve deliberate technical formats. Check logical layout edges, directional icons, gestures, and bidi isolation. Review HTML messages only through the existing sanitizing boundary.

Inspect catalogSections.js and catalog loaders when a key crosses surfaces. Chat messages must not depend on management-only catalogs. Do not make all catalogs eager to fix a missing translation.

Fix and verify

For authorized fixes, update the British source and all complete locales when the message contract changes. Add regional overrides only where needed. Keep uncertain linguistic findings separate from confirmed defects.

Run the focused i18n suite again after fixes. Run type checks and relevant component tests for changed call sites. For catalog-loading or chunk changes, run the frontend build, which includes check:i18n; the chunk check needs a current production build. Use e2e/translation-loading.test.ts for relevant navigation and loading regressions.

For visible behavior changes, use the user's browser tool preference to verify the affected surface in the source locale, the affected locale, and an RTL locale when direction matters. Check locale switching and narrow-screen text wrapping. Use mise dev when a server is needed and stop it afterward. If browser verification is unavailable, state the gap.

Report confirmed findings with paths, message keys, affected locales, and user impact. Separate fixes, remaining findings, and optional improvements. Include the commands run and the limits of automated and manual coverage. Do not claim that every translation is linguistically correct from structural tests alone.