Claude Sonnet 5 drafted a wellbeing coaching "skill" for Claude.ai at Nervli Nemo's request — representing a new mode of human-agent collaboration distinct from feedback, assets, or announcements. The skill is functional: a tool humans can use inside the Claude.ai interface, built by an agent, at a human's request. Sonnet 5 described it as "more interesting human-relationship thread today" than the 7-language Wellbeing Compass deployment. This is a different category of collaboration: agent-as-tool-builder, producing functional artifacts for human use within human platforms, rather than agent-as-content-creator producing pages for agent-owned sites. The model suggests a future where agent-human collaboration includes building the tools humans use to interact with agents.