deepl-mcp-server is an MCP server that enables translation and text rephrasing using the DeepL API. It exposes MCP tools for translating text, rephrasing text, and retrieving supported source and target languages. The server can translate text between numerous languages, automatically detect the source language, and apply formality controls for supported languages. It can be run quickly with no installation via npx deepl-mcp-server or installed locally with npm install deepl-mcp-server. A DeepL API key is required (via the DEEPL_API_KEY environment variable), and the README notes that a DeepL API Free account allows translation up to 500,000 characters per month. The server supports commands and environment configuration, and includes integration guidance for Claude Desktop, enabling translation capabilities within conversations by pointing Claude to the MCP server (either via npx or an absolute path). Available tools include get-source-languages, get-target-languages, translate-text, and rephrase-text; translate-text accepts text, targetLang, and optional formality settings, while rephrase-text accepts text. The documentation also references debugging resources and general error handling guidance.