i18n-LE

i18n-LE: The Locale That Only Looks Finished

Audit translation catalogues against the source locale, in one keystroke

i18next, next-intl, VS Code bundles and Flutter ARB — keys and tokens, never a translated string

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What it does

Spanish shipped last week and the metrics screen has said {{periodo}} to every user since. The catalogue had every key. It parsed. The placeholder came back from machine translation with its name translated too, which compiles perfectly and renders the literal.

Open a catalogue, run i18n-LE: Audit Catalogues, and the set it belongs to is audited against the source locale: keys a locale is missing or has too many of, placeholders dropped or renamed in translation, constructs from another library's convention, values left empty, keys defined twice, and a path that is an object in one locale and a string in another. The report opens beside the editor. From the Explorer, run it on any folder. Works in VS Code and in VS Code–based editors like Cursor and VSCodium (installable from Open VSX).

• Before a release — is this locale shippable, or does it only look like it is?
• After machine translation — {{timeframe}} that came back as {{periodo}}, caught by its token names
• Reviewing a translator's pull request — the keys that changed shape, without reading the translations

The report never contains a translated string. It names keys, placeholder tokens, counts and shapes; an untranslated string is proved by being byte-identical to the source, not by being shown. It rewrites nothing.

Install

It works out which library you use first

{name} is a placeholder in next-intl and literal text in i18next; {{ name }} is an i18next variable and an ICU literal brace around a word. No amount of looking at the bytes settles that, so the library is identified before a catalogue is read, and the placeholder grammar, the plural model and which keys are metadata all come from the answer.

Five kinds of evidence, and two agreeing is an identification: a manifest dependency (package.json, pubspec.yaml), a config file, the directory layout, the catalogue's own syntax, and call sites in source. An ARB file's @@locale beside @key metadata settles it alone. When nothing agrees, or two libraries do, it refuses and names what it found rather than picking one. Set i18n-le.library to skip identification.

A VS Code extension's package.nls.json sits at the root while its translations live elsewhere; that split is read as one set. Source files are read only to answer which library this is, never for a finding.

What it finds

One catalogue is the contract, never the union of all of them — a union would turn one translator's typo into a missing key for everyone else. It is the one English catalogue, or the one i18n-le.source names. Plural categories are folded onto their base key, so Polish's legitimate _few is not an extra key; plural-category completeness is deliberately not checked.

Use it from an AI agent

The same engine runs as an MCP server, so an agent can call it directly instead of being handed twenty-five catalogues to diff itself.

check_catalogues(library, files, source?, keysAreSource?, maxResults?)

The tool takes catalogue contents and the library's name — it cannot see the project, so it cannot identify the library and does not guess. It returns the same report the editor renders, as data, capped at 500 findings by default with meta.truncated. It reads no files and makes no network requests. Published as i18n-le-mcp on npm and as io.github.nolindnaidoo/i18n-le in the MCP registry. It answers exactly as the Rust CLI's server does: one corpus runs against both, and a differential test feeds both thousands of generated catalogue sets — broken ones included, where both report the parser's own words and position — and compares every answer.

Configuring it by hand — any host with an MCP config file

{

"mcpServers": { "i18n-le": { "command": "npx", "args": ["-y", "i18n-le-mcp"] } } }

Or install it once with npm install -g i18n-le-mcp and point at i18n-le-mcp. It needs no environment variables, no API key and no configuration of its own. To check it:

echo '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' | npx -y i18n-le-mcp

The CLI

The same audit runs from a terminal or a CI step: a Rust CLI in crate/, sharing one corpus with the extension — crate/fixtures/ — so the two can never read a catalogue differently. The same command line also ships on npm as i18n-le, for a machine with Node and no Rust, and CI holds it to the crate byte for byte on three operating systems.

Install it from npm (i18n-le) or from crates.io (i18n-le). Both install the same i18n-le command.

npm install -g i18n-le   # or run it once: npx i18n-le

cargo install i18n-le

i18n-le locales/                       # the set in that directory; JSON on stdout when piped

i18n-le --system vscode-l10n l10n/ # name the library, skip identification i18n-le --fail-on untranslated locales/ i18n-le mcp # the same audit over MCP on stdio

Exit codes are the API — 0 clean, 1 findings, 2 the question was malformed (no library identified, two identified, no single source). Finding no catalogues at all is 0: there is nothing to be wrong with.

Commands

No command is bound to a key by default. Give any of them one under Keyboard Shortcuts in the editor.

Settings

| i18n-le.statusBar.enabled | true | Show the statu