The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
Anthropic's[3] own announcement, dated the day the model became available.
Anthropic's[1][3] model reference page for Claude Opus 4.5 gives "Context window: 200K tokens · Max output: 64K tokens", text and images to text, extended thinking with default effort high, and a May 2025 reliable knowledge cutoff.
Anthropic's[1] Claude[2] Opus page lists this announcement and its date.
Something missing or wrong? Say it in your own words: a link that backs this pin up, a different start or end date and why, or a fact it lacks or gets wrong. The AI checks it against this pin's sources, searches for better ones, and adds any page that backs you up. The pin's own sources still count most.