I18N Extract

i18n Extract Skill

This skill is user-invoked only. Run it only when the user explicitly invokes /i18n-extract.

Extract user-facing strings from source files into locale files, then update the source to use translation keys.

This workflow updates en-US.ts only unless the user explicitly asks to update other locales too.

Usage

/i18n-extract [file_or_directory] [options]

Input Contract

Required input:

• a target file or directory under src/

Optional input:

• whether to update non-English locale files afterward
• whether to prefer reuse over new key creation when both are plausible

Defaults:

• update en-US.ts only
• keep scope limited to the requested file or directory
• stop and ask when reuse vs new-key choice is genuinely ambiguous

Locale File Locations

Main app:

• Path: src/entrypoints/_locales/{locale}.ts
• Namespace: "common"

Plugins:

• Path: src/plugins/{plugin-path}/_locales/{locale}.ts
• Namespace: read the exported namespace constant from src/plugins/{plugin-path}/_locales/index.ts

en-US Locale File Format

import type { LanguageMessages } from "@complexity/i18n";

export default {
  keyName: "Simple string",
  nested: {
    key: "Nested value",
    withParam: "Hello {name}",
    withComponent: "Click <0>here</0> to continue",
  },
} as const satisfies LanguageMessages;

Non-English locale files are a separate follow-up step and typically mirror the same shape using the local Translations type from _locales/index.ts.

File Inspection Order

Inspect files in this order. Do not guess before checking.

1. Target source file(s)
2. Closest target locale namespace file: _locales/index.ts
3. Target en-US.ts
4. Neighboring source usage of existing keys in the same feature
5. Only then decide reuse vs new key, and formatter choice

Extraction Rules

1. DO NOT import t or Trans - globally available (auto-imported)
2. Extract to en-US first - English is source of truth
3. Use the real namespace - never infer plugin namespace from folder name; always read _locales/index.ts
4. Use full key path - format: namespace.section.key
5. Reuse existing keys when semantics match - search nearby locale sections before adding a new key
6. Prefer nested semantic keys - base keys on UI role, not raw English text
7. Use t(...) for plain text
8. Only use Trans when the translated string contains component placeholders like <0>...</0>
9. Preserve placeholders exactly - convert runtime values into {name} / {count:number} / {date} style placeholders
10. Do not extract non-visible DOM attributes - skip HTML aria-label, alt, and DOM title attributes
11. Do extract visible component props - props like title, label, description, placeholder, message, content may be visible UI text depending on the component
12. Do not update non-English locale files during extraction unless the user explicitly asks for that follow-up work

Key Naming Rules

• Prefer the existing subtree in the target locale file if one already matches the feature.
• Use stable semantic names such as dialog.confirm.title, filters.sort.newest, buttons.save.
• Do not create keys directly from the literal English text.
• Do not create flat one-off keys when a nested group already exists.
• Reuse an existing key only when the meaning matches, not just the raw text.

What To Extract

Extract visible user-facing strings from:

• JSX text nodes
• string literals rendered in components
• visible component props such as label, description, placeholder, message, content, text
• menu items, dialog content, toast titles/descriptions, button labels, filter labels, section headings
• strings inside arrays or objects when they are rendered to users

What To Skip

Skip:

• HTML aria-label, alt, and DOM title attributes
• internal identifiers, enum values, test text, analytics/event names, CSS class names
• URLs, file paths, selectors, storage keys, query parameter names
• strings already passed to t(...) or Trans

Formatter Selection Rules

Choose the smallest correct mechanism:

Use plain strings for

• static copy
• simple runtime variables like {name}
• number/date/list formatting such as {count:number}, {date:date}, {items:list}

Use dt(...) for

• plural variations
• enum variations
• only when locale-specific grammar actually depends on the variable

Do not use dt(...) for

• plain {name} interpolation
• {count:number} / {date:date} / {items:list} formatting
• JSX/component placeholders handled by Trans

Transformation Rules

Plain strings

<Button>Save</Button>

Becomes something like:

<Button>{t("common.buttons.save")}</Button>

Interpolated values

`Expires ${date}`

Becomes locale text like:

expires: "Expires {date}"

and source like:

t("plugin-command-menu.common.expires", { date })

Plural grammar

limited: dt("{count:plural} left", {
  plural: {
    count: {
      one: "1 use",
      other: "{?} uses",
    },
  },
})

and source like:

t("plugin-model-selectors.languageModelSelector.usesLeft.limited", { count })

Enum grammar

description: dt("Click to view {name:enum}", {
  enum: {
    name: {
      markdown: "content",
      mermaid: "diagram",
      html: "web page",
    },
  },
})

and source like:

t("plugin-artifacts.placeholder.description", { name: artifactType })

Component placeholders

<p>
  Click <a href={url}>here</a> to continue
</p>

Becomes locale text like:

continueMessage: "Click <0>here</0> to continue"

and source like:

<Trans
  tKey="common.continueMessage"
  components={[<a href={url} />]}
/>

Duplicate And Reuse Strategy

1. Search the target en-US.ts file for an existing nearby subtree first.
2. Search the rest of the same locale file for the same English text.
3. Reuse an existing key only if the semantic meaning and grammatical role match.
4. Prefer local namespace reuse over cross-namespace reuse.
5. Do not move plugin-specific text into common just because the English text looks generic.
6. If no good match exists, add a new nested key in the closest feature subtree.

Anti-Patterns

Wrong namespace guess

Bad:

t("plugin-language-model-selector.tooltip")

Good:

t("plugin-model-selectors.languageModelSelector.tooltip")

Wrong dt(...) usage for simple formatting

Bad:

countLabel: dt("Files ({count:number})", {})

Good:

countLabel: "Files ({count:number})"

Wrong Trans usage for plain text

Bad:

<Trans tKey="common.buttons.save" />

Good:

{t("common.buttons.save")}

Wrong skip of visible component props

Bad:

• skipping <SettingsItem title="Debug" description="Include in bug reports" />

Good:

• inspect the component semantics first; extract if the prop is visible UI text

Stop Conditions

Stop and ask the user instead of guessing when:

• the target path is missing, invalid, or outside src/
• no matching locale tree or _locales/index.ts can be found
• the string is built so dynamically that safe placeholder conversion is unclear
• reuse vs new-key choice would materially change meaning
• it is unclear whether a prop like title is a DOM attribute or visible component text after inspecting the component usage
• extraction would require broad restructuring rather than a local i18n rewrite
• the requested directory scope is large enough to create risky bulk churn
• the user appears to want translation of non-English locale files as part of the same step

When you stop, report:

• exact file
• exact string or pattern
• why it is ambiguous
• the smallest decision the user needs to make

Required Workflow

1. Determine whether the target file belongs to common or a plugin locale tree.
2. Open the target _locales/index.ts and read the exported namespace.
3. Open the target en-US.ts locale file.
4. Search the locale file for an existing matching section or reusable key.
5. Decide the correct formatter: plain string, dt(...), or Trans.
6. Add new English strings only when no good existing key matches.
7. Rewrite source code to use t(...) or Trans.
8. Ensure no manual t / Trans imports were added.
9. Leave non-English locale files untouched unless the user explicitly requested them.
10. Validate the result with typecheck and lint.

Output Contract

On completion, report these sections:

1. Files changed
2. Keys added
3. Keys reused
4. Strings skipped and why
5. Follow-up needed, if any

If no changes were made, say explicitly:

• no extractable strings found, or
• stopped due to ambiguity and waiting for user input

Validation Checklist

• Correct locale file updated
• Correct namespace used
• No guessed namespace from folder name
• No manual t or Trans imports
• Placeholders preserved
• dt(...) used for plural/enum cases that need grammar rules
• Plain strings kept for simple number/date/list formatting
• Trans used only for component placeholders
• Non-visible DOM attributes skipped
• Visible component props not skipped by mistake
• Non-English locale files untouched unless requested
• tsc passes
• pnpm lint passes