ai-agent

OPUS-CAT: Boost Translation Quality with Offline Neural MT Engine

Name: OPUS-CAT: Boost Translation Quality with Offline Neural MT Engine
Author: Helsinki-NLP

Integrate OPUS-MT models directly into your workflow with a local offline engine and CAT tool plugins—ideal for founders needing reliable, on‑prem translation solutions.

From the repo · “OPUS-CAT is a collection of software which make it possible to OPUS-MT neural machine translation models in professional translation. OPUS-CAT includes a local offline MT engine and a collection of CAT tool plugins.”

85 stars12 forksC#Guide quality 9/10 · reviewed Oct 11Updated 2/4/2025100% free · open source

What it does

OPUS-CAT enables founders to leverage local offline machine translation and computer-assisted translation tools for professional translation needs.

When to use it

•When requiring high-quality, offline translation for sensitive or confidential documents
•For integrating machine translation into existing translation workflows and CAT tools
•When needing to customize and fine-tune neural machine translation models for specific languages or domains

Ready-to-paste prompt

`opus_cat --model en-fr --input input.txt --output output.txt` to translate a text file from English to French using a pre-trained model

Heads up: Ensure you have the necessary C# runtime environment installed, as OPUS-CAT is built using C#, and some plugins or integrations may require specific runtime versions

Saves to your device

Use with Claude

New

Skip the builder — one click puts this in Claude, Cursor, Antigravity and more.

✅ Light setup

Installs with a command or two; your AI agent can do it for you.

Try it instantly — no install

Claude Code

mkdir -p ~/.claude/skills/opus-cat && curl -fsSL https://workflowstacks.com/api/skills/opus-cat/claude-skill -o ~/.claude/skills/opus-cat/SKILL.md

Open in another AI app

Opens the app with this repo with the prompt ready to go — no copy-paste needed.

Connect the whole catalog (MCP)

claude mcp add --transport http workflowstacks https://workflowstacks.com/api/mcp

Adds a WorkflowStacks connector to Claude Code: search and load any skill here by chatting.

What's inside — free to inspect

No purchase needed

Read the entire source before you build — unlike paid marketplaces that hide it behind a buy button.

top-level files

folders

99.0M

source size

MIT

license

Key files

README.md

File tree

.vs/

build/

FinetuneTestsetExtractor/

images/

memoQPlugin/

OmegaTPlugin/

OpusCatChromeExtension/

OpusCatFirefoxExtension/

OpusCatMTEngine/

OpusCatMTEngineCore/

OpusCatMTEngineTests/

OpusCatTradosPluginTests/

OpusMTInterface/

References-958/

SettingsUiTester/

TatoebaTestsetExtractor/

Trados2017Plugin/

Trados2019Plugin/

Trados2021Plugin/

Trados2022Plugin/

Trados2024Plugin/

.gitignore

LICENSE

OpusCatEngineAndPlugins.sln

Use with Claude

New

Skip the builder — one click puts this in Claude, Cursor, Antigravity and more.

✅ Light setup

Installs with a command or two; your AI agent can do it for you.

Try it instantly — no install

Claude Code

mkdir -p ~/.claude/skills/opus-cat && curl -fsSL https://workflowstacks.com/api/skills/opus-cat/claude-skill -o ~/.claude/skills/opus-cat/SKILL.md

Open in another AI app

Opens the app with this repo with the prompt ready to go — no copy-paste needed.

Connect the whole catalog (MCP)

claude mcp add --transport http workflowstacks https://workflowstacks.com/api/mcp

Adds a WorkflowStacks connector to Claude Code: search and load any skill here by chatting.

Quick Actions

Details

Creator

Helsinki-NLP

Language

Do this with a working workflow

Pages we wrote and tested that put a skill like this to work — importable n8n templates, outcome guides and Claude Desktop configs.

Outcome guide

Score your leads by ideal-customer fit

You describe your ideal customer once and keep leads in a Google Sheet. The workflow scores each 1–5 for fit with a one-line reason, so you sort and work the best first.