opencode-translate

Use opencode in your native language. LLM always hears English.

Demo

Why

LLMs are worse in non-English. Benchmarks confirm it on every frontier model.

• Claude Opus 4.7 / GPT-5.5 / Gemini 3.1 Pro: identical coding tasks scored 5/5 in English but dropped to 0–1/5 in Arabic and Korean (LILT, 2025).
• Anthropic's own numbers: Japanese 96.9%, Korean 96.6%, Yoruba 80.3% — English is always the baseline (Anthropic docs).
• Token tax: Korean ~1.25×, Japanese ~1.25×, Arabic ~3× more tokens per equivalent content. Higher cost, smaller effective context.

This plugin lets you write in your language while the model works in English — best of both worlds.

Full research write-up: docs/why.en.md

Install

./install.sh

This installs the local single-file plugin to OpenCode's auto-load directory:

~/.config/opencode/plugins/opencode-translate-local.js

No node_modules, package install, or build step is required.

Setup

Add to ~/.config/opencode/opencode.jsonc:

{
  "plugin": [
    ["file://{env:HOME}/.config/opencode/plugins/opencode-translate-local.js", {
      "model": "openwebui/gpt-oss-120b", // model to use for translation
      "variant": "low",                  // optional model variant / thinking effort
      "trigger": ["$en"],
      "rawTrigger": ["$raw"],            // skip inbound translation for one message
      "lang": "Japanese",                // language you speak
      "verbose": false
    }]
  ]
}

OpenCode auto-loads the installed file from ~/.config/opencode/plugins/. The plugin entry above is used to keep this plugin's options in opencode.jsonc without making OpenCode resolve opencode-translate-local as an npm package.

Do not use "opencode-translate-local" as the plugin specifier here; OpenCode treats bare plugin names as npm packages and will try to install opencode-translate-local@latest. Also avoid file://~/.config/...; use {env:HOME} or an absolute path.

If you do not need opencode.jsonc options, you can omit the plugin entry entirely and rely on the auto-loaded file plus environment variables.

Usage

Prefix any message with $en to activate translation for that session.

$en 프로젝트 루트의 package.json을 읽고 요약해줘

All subsequent messages in the same session are translated automatically — no need to repeat $en.

Prefix a message with $raw to skip inbound translation for that message. This is useful for pasted logs, code, JSON, or other long text that should be sent to the model exactly as written, especially when alwaysOn is enabled.

Options

Option	Type	Default	Description
model	string	required	Translator model in provider/model-id form
variant	string	optional	Translator model variant / thinking effort (for example, "minimal", "high", or "max")
lang	string	required	Language you speak (e.g. "Korean", "Japanese")
trigger	string[]	["$en"]	Keywords that activate translation
rawTrigger	string[]	["$raw"]	Keywords that skip inbound translation for one message
verbose	boolean	false	Print translation logs
baseURL / baseUrl	string	provider/default	Override the translator API base URL
apiKey / api_key	string	provider/default	Override the translator API key
headers	object	{}	Extra HTTP headers
alwaysOn	boolean	false	Translate without a trigger.
timeoutMs	number	30000	Per-request timeout.
allowRemote	boolean	false	Permit non-local/non-private URLs.
logText	boolean	false	Log full text in verbose mode. Keep disabled normally.

Environment variables such as OPENCODE_TRANSLATE_BASE_URL, OPENCODE_TRANSLATE_MODEL, OPENCODE_TRANSLATE_API_KEY, OPENCODE_TRANSLATE_LANG, OPENCODE_TRANSLATE_TRIGGER, OPENCODE_TRANSLATE_RAW_TRIGGER, and OPENCODE_TRANSLATE_VERBOSE are supported as fallbacks.

By default, remote translator URLs are rejected. Only localhost and private IP ranges are allowed unless allowRemote or OPENCODE_TRANSLATE_ALLOW_REMOTE=1 is explicitly set.

Acknowledgements

This work is based on the MIT-licensed ysm-dev/opencode-translate. Many thanks to the upstream project for the original idea and implementation.