Tools

Pluggable natural-language linter that checks Markdown and plain text for wording, punctuation and terminology consistency like code, with auto-fix, and can also run as an MCP server. Rules are installed separately, mostly for Japanese and English; requires Node.js 20+.

Translation management for Ruby/Rails: statically analyzes code to find missing and unused keys, normalizes locale files, fills gaps via Google Translate, DeepL or OpenAI, and exports CSV for translators. Requires the i18n gem (Rails default) and Bundler; machine translation needs an API key.

One plugin bundling skills and subagents for deep research, fixing GitHub issues and reviewing PRs, Codex handoff, Gemini or GPT image generation, translation and YouTube transcript extraction, plus settings.json templates for various providers (manual setup). Some skills need API keys.

Sets up and audits i18n for React, Next.js and Vue apps: replaces hard-coded strings with message keys, checks that English and Chinese keys are complete and consistent, and verifies plurals and date and number formats, with a key audit script. Needs a local codebase and Python.

The standard machine translation scorer: computes BLEU, chrF and TER with significance tests and downloads public test sets such as WMT, to compare engines or prompts. Needs Python 3.9+ and reference translations; automatic metrics are a rough screen, so final copy still needs human review.

General Translation's gt CLI: a wizard sets up i18n for React, Next.js and similar apps, then sends UI strings and JSON, YAML or Markdown files for AI translation and writes them back, with CI support. Needs a Node.js project and a General Translation API key (free sign-up, usage-based pricing).

Open-source toolkit widely used in localization: converts between PO, XLIFF, TMX, CSV, subtitle and other translation formats, counts words, runs 40+ translation checks with pofilter and extracts frequent terms with poterminology. Needs Python 3.11+.

Microsoft's official skill: has the agent use Microsoft Learn docs to call Azure text and document translation, enforce glossaries, train Custom Translator models and troubleshoot quotas and errors. For localization teams building batch translation; needs an Azure account and Translator resource.

Unbabel's machine-translation quality metric: comet-score rates translations per sentence and overall, XCOMET marks error spans and severity, and CometKiwi works without a reference. Good for spot-checking MT. Needs Python 3.8+; models download from Hugging Face, some need a license; GPU helps.

Official ElevenLabs skills: text to speech, speech to text, sound effects and music generation, voice changing, vocal isolation, multilingual dubbing and building voice agents. Needs an ElevenLabs API key.

i18next's official CLI: finds hard-coded strings in JS/TS code, extracts translation keys, checks which locales are missing entries and syncs locale files; init --yes sets up non-interactively, and a bundled agent skill guides app internationalization. Needs a Node.js project using i18next.

Microsoft Translator's translation quality tool: GPT scores each sentence using MQM error categories or a direct score; --list_mqm_errors shows error types and severity. Needs line-aligned source and target files, Python and an OpenAI or Azure OpenAI key (paid); a translator should still review.

Official CLI for Weblate, the open-source translation platform: check translation progress for projects and components, upload and download translation files, lock components, and commit or push repository changes. Hosted or self-hosted; needs the server URL, an API key and Python.

Community MCP for Weblate, the open-source translation platform (self-hosted or hosted): translators can find untranslated or needs-editing strings in plain language, write translations in bulk, and check per-language progress and change history. Needs your Weblate API URL and token, and Node.js.

Crowdin's official plugin with the Crowdin MCP: manage projects and translations in Claude Code, Cowork or Codex, with skills to build glossaries, add translator context, draft translations for review and answer how-tos. Needs a Crowdin account; drafts and glossary uploads need its CLI.

Locize's official plugin: agents translate and review strings using your project's glossary, style guide and translation memory, and check new copy for banned terms; also bundles the Locize MCP and an i18next skill for developers. Needs a Locize account (free tier); browser auth or a personal token.