i18n-le-mcp

An MCP server that audits a set of translation catalogues against one of them — missing and extra keys, placeholders dropped or renamed in translation, constructs from another i18n convention, empty values, keys defined twice, and a path that is an object in one locale and a string in another — the audit engine behind the i18n-LE editor extension, exposed as a tool an agent can call.

Only key names and structural facts come back — never a translated string. An agent asking whether Spanish is complete does not need the Spanish: a renamed placeholder is proved by its tokens, and an untranslated string by the fact that it is byte-identical to the source.

The library is named, never guessed. Which library wrote a catalogue decides what {name} means — a placeholder in next-intl, literal text in i18next — and working that out needs manifests, config files and call sites, none of which this server can see. The caller names it, or gets a refusal.

No dependencies, no network calls, no filesystem access. Content goes in, structured results come out.

Use it

Point any MCP host at npx i18n-le-mcp.

Claude Code

claude mcp add i18n-le -- npx -y i18n-le-mcp

Anything with a JSON config — Cursor, Windsurf, Claude Desktop:

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

VS Code needs nothing here. Install the extension instead — it carries this server and registers it for you: VS Code Marketplace · Open VSX

No Node? The same check_catalogues tool ships in a static Rust binary: cargo install i18n-le, then i18n-le mcp (crates.io). The two servers answer identically — one corpus runs against both, and a differential test feeds both thousands of generated catalogue sets, broken ones included, and compares every answer. This server reads no files.

Prefer a global install to npx on every launch:

npm install -g i18n-le-mcp

{
  "mcpServers": {
    "i18n-le": { "command": "i18n-le-mcp" }
  }
}

No environment variables, no API key, no configuration of its own. To check it before wiring it into anything:

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

If that prints the tool name, the server works.

The tool

check_catalogues

| argument | type | | |---|---|---| | library | string | required. Which library wrote the catalogues: i18next, next-intl, vscode-l10n or flutter-arb. It supplies the placeholder grammar, the plural model and which keys are metadata. | | files | object[] | required. The catalogues, each { path, content } with an optional locale. JSON, nested or flat. A locale left out on every file is read from the names together. | | source | string | Which catalogue is the contract — a path or a language tag. Without it, exactly one English candidate must exist or the audit is refused. | | keysAreSource | boolean | The key is itself the English string, as in a VS Code bundle.l10n.json. | | maxResults | number | Default 500, ceiling 5000. |

Findings name the file and the key, and carry only structural evidence — tokens, counts, styles, shapes, occurrence counts, or a construct and its byte offset:

{
  "ok": true,
  "data": {
    "schema": 3,
    "status": "findings",
    "system": { "library": "i18next", "version": null, "layout": null, "keysAreSource": false, "evidence": [] },
    "source": { "path": "en.json", "locale": "en", "keys": 2 },
    "files": [
      { "path": "en.json", "locale": "en", "keys": 2 },
      { "path": "es.json", "locale": "es", "keys": 1 }
    ],
    "findings": [
      { "severity": "error", "kind": "missing-key", "file": "es.json", "key": "nav.home" },
      {
        "severity": "error",
        "kind": "placeholder-name-mismatch",
        "file": "es.json",
        "key": "metrics.window",
        "sourceTokens": ["timeframe"],
        "targetTokens": ["periodo"]
      }
    ],
    "diagnostics": [],
    "summary": { "files": 2, "findings": 2 }
  },
  "diagnostics": [],
  "meta": { "tool": "check_catalogues", "count": 2, "truncated": false }
}

A catalogue that will not parse is named in diagnostics with the parser's reason and position, and the rest are still audited. ok means the audit ran, not that the answer was yes.

Also in the MCP registry

io.github.nolindnaidoo/i18n-le — registry.modelcontextprotocol.io

Eleven more like it

One tool each, same shape: content in, structured data out, no network and no filesystem. Every one is on npm as <name>-mcp and in the MCP registry as io.github.nolindnaidoo/<name>.

| Package | Tool | Does | |---|---|---| | urls-le-mcp | extract_urls | URLs, with protocol and position | | colors-le-mcp | extract_colors | colors from stylesheets and code | | dates-le-mcp | extract_dates | dates and timestamps | | numbers-le-mcp | extract_numbers | numeric values | | paths-le-mcp | extract_paths | file and directory paths | | string-le-mcp | extract_strings | string values | | regex-le-mcp | extract_patterns | regexes, with a ReDoS verdict | | secrets-le-mcp | detect_secrets | credentials, masked — never the value | | envsync-le-mcp | compare_env_files | dotenv key drift, names only | | scrape-le-mcp | analyze_robots_txt | whether a path may be crawled | | unicode-le-mcp | detect_unicode_risks | Unicode that hides meaning, as codepoints |

Every tool in the family, one page: letools.dev

Built by

Nolin Naidoo — Chief Engineer, AI/ML & Platform Architecture. nolindnaidoo.com · GitHub · LinkedIn

Also from the same workshop

Twelve Rust tools built the same way: small, single-purpose, and driven by a machine rather than a person. pixelcoords and pixelactions make up one loop — pixelcoords answers where, pixelactions acts there. The ten LE crates are the terminal half of the extensions they sit in: the same detection, held to the extension's own corpus, and an exit code instead of a results editor.

| | | | |---|---|---| | pixelcoords | Freeze your screen, mark regions, get pixel-exact coordinates and crops | site · crates.io · docs.rs | | pixelactions | Consume human-verified coordinates, perform the interaction, confirm it landed | site · crates.io · docs.rs | | paths-le | Find every path in a codebase and report whether it still points at anything | crates.io | | secrets-le | Find hardcoded credentials, and never print one | crates.io | | urls-le | Extract every URL from a codebase, with its protocol and exact position | crates.io | | regex-le | Find every regex in a codebase and report which can be driven into catastrophic backtracking | crates.io | | string-le | Get every string in a codebase out where a person can read them | crates.io | | numbers-le | Find every hardcoded number in a codebase so a person can check them | crates.io | | envsync-le | Compare the dotenv files in a tree and say which keys are missing from which | crates.io | | colors-le | Find every colour in a codebase, and say which are not in your palette | crates.io | | dates-le | Extract every date and timestamp, and the exact instant each one resolves to | crates.io | | scrape-le | Check whether a page is scrapeable before the scraper is written | crates.io |

Licence

MIT © Nolin Naidoo