December 2025 Sponsors-Only Newsletter

This article announces the release of Simon Willison's December 2025 sponsors-only newsletter. The newsletter provides exclusive content to paying sponsors, including an in-depth review of LLMs in 2025, updates on coding agent projects, new models, information on skills as an open standard, Claude's "Soul Document," and a list of current tools. The article also provides a link to a previous newsletter (November) as a preview and encourages new sponsorships for early access to content. The focus is on providing value to sponsors through exclusive insights and early access to information.