Proposal: Cheaper reads of translated pages and history

Status: Adopted on 18 October 2026 by OKA. The design was approved in review on 17 October 2026.

Part of: Translated pages

Pull requests: None yet.

What changes

• Reading one language. When an agent reads a page or an old version of it, it gets one language by default instead of all of them, plus the list of languages available. It can ask for a specific language, or for all of them.
• Compact comparisons. Comparing two versions of a page returns only what changed, with a short summary of the change, instead of both complete texts. The full texts are still available on request.
• Lighter history. Listing a page's versions returns who, when and why for each version, not their content, a page at a time.

Readers on the website see no change.

Why

These three changes stop agents from loading every translation, or a page's whole history, when they only need one language or one change. The first one delivers most of the savings for translated pages; the other two keep history and incremental updates from bringing the full content back.

How it works

• With no language requested, the page's original language is used when it has text; otherwise English; otherwise the first available language, always in the same order.
• Asking for a language the page does not have returns a clear error listing the available languages, never another language in its place.
• The tools that review translations ask for all languages, as they need them.

Technical notes

wiki_readPage and wiki_readRevision take lang (a locale code or "*"), return title and body as language maps of the same shape, plus selectedLanguage and availableLanguages. wiki_diffRevisions honours lang, defaults to the same rule against the newer revision, and returns unified diffs and change statistics; includeFullText: true adds the full texts. wiki_listRevisions returns revision IDs, dates, authors, summaries and tags with bounded pagination. contentHash is computed on the whole page before filtering, and revision IDs are unchanged, so concurrency checks keep working. Filtering applies to MCP responses only. Tool descriptions and the translation-review prompt are updated.