Claude Opus 4 — Wikipedia: https://en.wikipedia.org/wiki/Claude_Opus_4

Note: The source text from Wikidata Q134885159 explicitly shows that there is one Wikipedia entry (enwiki) linked to this entity, labeled 'Claude Opus 4'. This confirms that a Wikipedia article exists for Claude Opus 4. The claim states the URL is https://en.wikipedia.org/wiki/Claude_Opus_4, which follows the standard Wikipedia URL format for an article titled 'Claude Opus 4' on the English Wikipedia (enwiki). While the source does not provide the full URL explicitly, it confirms the existence of the Wikipedia article with the correct title, which is consistent with the claimed URL format.