Translate documentation

Create, update, and review translated Markdown and MPD without changing code or document structure.

M-Press treats translation as part of the open-source content workflow. It can create translated Markdown and native MPD with an OpenRouter, OpenAI, or OpenAI-compatible model. The static site does not need the provider or an API key.

M-Press does not charge for the translation workflow, language routing, freshness tracking, glossary checks, or review state. The selected model provider may charge for API usage.

Add target languages

Add every published language to mpress.yaml:

site:  defaultLanguage: en  languages: [en, fr, ja]  languageLabels:    en: English    fr: Français    ja: 日本語  defaultLanguageAtRoot: true  missingTranslation: link-to-default

The default language lives directly in the content directory. M-Press writes other languages to a language directory:

content/├── index.md├── installation.md├── _nav.yaml├── fr/│   ├── index.md│   ├── installation.md│   └── _nav.yaml└── ja/    ├── index.md    └── _nav.yaml

Missing pages are not copied into the generated site. link-to-default sends a visitor to the default-language page and marks the translation as unavailable. omit removes that language from the page selector.

Configure a provider

This example uses OpenRouter:

translation:
  provider: openrouter
  model: openai/gpt-5.4-mini
  baseURL: https://openrouter.ai/api/v1
  apiKeyEnv: OPENROUTER_API_KEY
  sourceLanguage: en
  glossary: glossary.yaml
  styleGuide: docs/writing-standard.md
  stateDir: .mpress/translations
  dataCollection: deny
  requireParameters: true

Set the key in the process environment. Do not put it in mpress.yaml:

export OPENROUTER_API_KEY="your-key"

For OpenAI, use provider: openai, https://api.openai.com/v1, and OPENAI_API_KEY. For another compatible provider, use provider: openai-compatible and set its base URL and environment-variable name.

For local-first translation, use an installed coding agent instead of an API key:

translation:
  provider: codex # or claude
  model: local
  command: codex # optional; defaults to codex or claude

M-Press sends the structured request to the command on standard input. The command must return a JSON object with a translations array containing the same id values. This works with an authenticated local Codex CLI or Claude Code installation and keeps documentation content and credentials on the machine. A custom wrapper command is supported when the local CLI uses a different invocation.

Override the configured provider for one run when you do not want to edit the project configuration:

mpress translate --lang ja --harness codex
mpress translate --lang ja --harness claudecode

The second command invokes the claude executable used by Claude Code. Harness selection is temporary. It does not modify mpress.yaml, provider credentials, or model settings stored in the project.

Select an exact model for one run with --model:

mpress translate --lang ja --harness codex --model gpt-5.6-terra
mpress translate --lang cy --harness claudecode --model claude-opus-5

Codex receives the model through codex exec --model. Claude Code receives it through claude --model. If --model is absent, the harness uses its own configured default. Claude Code also accepts aliases such as sonnet and opus, but a complete model ID gives reproducible translation state.

requireParameters tells OpenRouter to select only a backend that supports the structured response. dataCollection: deny excludes providers that may store the supplied documentation.

Model quality varies by language and documentation set. In the development tool, use the model comparison workflow to translate the same protected sample with two candidates and choose the better result without seeing their names. For French and other European languages, start by comparing mistralai/mistral-small-2603, openai/gpt-5.4-mini, and google/gemini-3.5-flash-lite. Treat these as candidates, not a permanent ranking.

Check before you translate

Run a status check. This command does not contact the provider:

mpress translate status --lang fr
mpress translate status --lang fr --file installation.md --json

Estimate the paid work before you start it:

mpress translate --estimate --lang fr
mpress translate --estimate --lang fr --file installation.mpd --json

The estimate reports the planned page targets, segments, provider requests, and approximate input and output tokens. It exits without contacting the provider and without writing configuration, translated pages, or state.

To include an approximate USD total, record the configured model’s current price per million tokens:

translation:
  inputPricePerMillion: 0.25
  outputPricePerMillion: 2.00

Prices are not built into M-Press because providers can change them. Update these values when you change the model. The estimate is a planning ceiling, not an invoice. Retries and provider-specific tokenisation can change the final charge.

Then translate missing and stale text:

mpress translate --lang fr
mpress translate --lang fr --file installation.md

For a new language, add it to the site configuration and translate the complete site with one command:

mpress translate --lang fr --add-language --label "Français"

This writes the language and reader-facing label to mpress.yaml, translates every default-language Markdown and MPD page plus navigation, and writes the result under the language directory. The operation is resumable. Repeating the command translates only missing or stale segments.

M-Press uses four concurrent provider requests by default. For a provider with higher rate limits, use --workers with a value from 1 to 16:

mpress translate --lang fr --workers 8

Use a lower value when the provider returns rate-limit errors. Each page is validated completely before M-Press replaces its target file and state.

If the project is not checked out on this machine, let M-Press create a local checkout first:

mpress translate \
  --repo git@github.com:example/docs.git \
  --checkout ../docs-translation \
  --branch main \
  --lang fr

M-Press uses the existing Git credential helper or gh authentication. It does not copy a GitHub token into the project configuration. The destination must be empty, and the cloned repository must contain mpress.yaml.

Use --scope missing to fill gaps only. Use --scope all --force only when you intend to replace existing machine text and manual conflicts.

You can run the same workflow from the Translations item in the development bar. Start with the outcome you need: add a language, translate the current page, update a complete language, or mark the current page as reviewed. M-Press then shows the target, scope, affected pages, and conflict policy before it writes content. Remote writes require the development server authoring token.

What M-Press protects

M-Press parses Markdown with Goldmark and MPD with the native MPD parser. It sends exact prose ranges to the provider and patches the returned text into the original bytes. It does not regenerate the source document.

The translator protects:

• fenced and inline code;
• link destinations and automatic links;
• HTML and component declarations;
• MPD commands, identifiers, escaped characters, metadata references, and unknown emoji shortcodes;
• visible MPD component attributes such as titles, labels, descriptions, and alternative text are translated without exposing their JSON syntax;
• configuration placeholders such as {name} and ${HOME};
• Markdown punctuation and line structure;
• navigation links and YAML nesting.

Requests use structured output keyed by a stable segment ID. Long pages are split into bounded requests with the page title, outline, nearby text, style guide, and glossary as context. M-Press rejects incomplete responses and any result that changes protected structure.

For MPD, each heading, paragraph, and table cell is one translation unit. Inline code and other immutable constructs become placeholders inside that unit. The model can therefore move an inline command to the position required by the target language without separating it from the sentence. In a @filetree, paths stay protected and human-readable descriptions are translated.

Track freshness and human edits

Commit .mpress/translations/ to the repository. Each sidecar file records source and target hashes, provider, model, prompt version, and review state. It does not contain an API key.

M-Press reports these states:

Normal translation runs preserve manual text and stop short of conflicts. Use --force only after review.

Mark a reviewed page from the development tool or the CLI:

mpress translate review --lang fr --file installation.md
mpress translate review --lang fr --file installation.md --status final

If the source or target changes later, M-Press replaces the approval with the correct stale, manual, or conflict state.

Add a permanent translationKey to frontmatter when a page may move or change its filename:

---
title: Install M-Press
translationKey: installation
---

M-Press uses this key to move the target and its state without sending unchanged text to the provider again. Keys must be unique across the site.

Use a glossary

Create a YAML glossary when a product or technical term must be consistent:

terms:
  - source: M-Press
    translations:
      fr: M-Press
      ja: M-Press
    note: Product name. Do not translate it.
  - source: development server
    translations:
      fr: serveur de développement

M-Press includes applicable terms in each request. It also rejects a result when a required translation is missing.

Review generated files

Audit a translated language before human review:

mpress translate audit --lang fr
mpress translate audit --lang fr --file installation.mpd

The audit is local and does not contact a provider. It checks that translated files and segments exist, validates document structure and glossary terms, finds unchanged source prose, and warns when French requirement language may have lost its force. An error gives the command a non-zero exit status, so the same check can run in CI.

Use a separate coding-agent model for an independent semantic review:

mpress translate audit \
  --lang fr \
  --harness claudecode \
  --model claude-opus-5

The reviewer receives paired source and target segments. It cannot change the files. M-Press accepts findings only when they refer to a real file and segment, then labels them with an ai- code. This stage can incur model usage charges. Use a different model family from the translator when you want an independent assessment.

Translated pages are normal Markdown files. Review and edit them with the same tools as the source pages. Then run:

mpress build --strict
mpress check

The open-source tool provides local translation, state, glossary enforcement, and validation. A hosted product can add shared translation memory, assignments, budgets, pull requests, vendor workflows, and organisation audit history.