add_translation_key
Add a specific translation key with values to specified languages and namespaces
LABSCO SUMMARY
It closes the loop between the keys your code calls and the keys your locale files carry.
Reporting and writing are separate halves of the same set: coverage, quality and usage analysis say what is absent, and the sync tools then add those keys from a source language in sorted order, with a backup available and a dry run on the bulk paths. Because the scanner reads source code for keys that never reached a file, drift shows up from both directions. Translation itself stays out of scope — the sync tools copy values across or drop in a placeholder, leaving the wording to whoever does the language work.
What it is
A server over an i18next project's locale files that reports on their coverage and quality, and writes missing keys back into them.
What you get
- A health check across the translation files, with per-language and per-namespace detail, and JSON syntax and structure validation that can fix what it finds.
- Coverage and quality reports by language and namespace, plus a listing of every translation file.
- Key usage analysis against your source paths, and a scan that finds keys used in code with no entry in the files.
- A detailed list of missing keys by language and namespace, in a format you choose.
- Sync paths that fill the gaps from a source language — named keys, chosen namespaces, or everything missing at once — each able to take a backup first, with a dry run available on sync_missing_keys and sync_all_missing.
- A single-key write that adds a key with its values to named languages and namespaces, and an export of translation data in various formats.
Requirements
An i18next project on disk, and four environment variables telling the server where it lives and what it covers: I18N_PROJECT_ROOT, I18N_LOCALES_PATH, I18N_DEFAULT_LANGUAGE and I18N_SUPPORTED_LANGUAGES.
Setup effort
One command — npx -y i18next-mcp-server@latest
USE CASES
01
Working out why one language is showing raw keys on screen
A health check over the translation files narrows it to a language and namespace, the missing-key list names the exact keys, and the file listing shows which file should have carried them.
02
Catching a new locale up before a release
Coverage shows how far behind the language is, the bulk sync adds every missing key with a placeholder and a backup, and validation confirms the files are still structurally sound.
03
Finding keys the code calls that nobody ever translated
The scanner reads your source paths for keys with no entry in the files, usage analysis shows where each one is referenced, and the selected keys are copied over from the source language.
04
Adding one string to every language at once
A single key with its per-language values goes into the named namespaces in one call, with a backup taken before the files are touched.
05
Handing the outstanding strings to a translator
The missing keys come out by language and namespace in the format you ask for, and the export carries the current translation data alongside them.
14 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
coverage_report
Generate comprehensive coverage report for translations
export_data
Export translation data in various formats
get_missing_keys
Get a detailed list of missing keys by language and namespace for targeted translation work
get_project_info
Get information about the translation project configuration and status
health_check
Perform comprehensive health check on translation files
list_files
List all translation files with their basic information
quality_analysis
Analyze translation quality across files
scan_code_for_missing_keys
Scan code for missing keys using the scanner integration
sync_all_missing
Comprehensive sync to add all missing keys across all languages, ensuring complete coverage
sync_from_source
Sync specific missing keys from source language to target languages
sync_missing_keys
Synchronize missing translation keys across all languages from a source language, maintaining sorted structure
usage_analysis
Generate detailed usage analysis of translation keys
validate_files
Validate translation files for JSON syntax and structure issues
BEFORE YOU INSTALL
What to know first
Tools you get
14 tools when we connected.
Requires
- npx on PATH
- I18N_PROJECT_ROOT in your environment
- I18N_LOCALES_PATH in your environment
- I18N_DEFAULT_LANGUAGE in your environment
- I18N_SUPPORTED_LANGUAGES in your environment
CONTEXT COST
Light Standing cost
Rated by the size of the 14 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Add the block to your client, or run the command directly.
Server setup
Configuration file
JSON
{
"mcpServers": {
"i18next-translation": {
"command": "npx",
"args": [
"-y",
"i18next-mcp-server@latest"
],
"env": {
"I18N_PROJECT_ROOT": "<YOUR_I18N_PROJECT_ROOT>",
"I18N_LOCALES_PATH": "public/locales",
"I18N_DEFAULT_LANGUAGE": "en",
"I18N_SUPPORTED_LANGUAGES": "en,es,fr"
}
}
}
}npx
TERMINAL
npx -y i18next-mcp-server@latest
