Signal

**The adaptive health-messaging engine for apps and agents — federally-sourced, audience-safe facts, lists & tips, keyless to try.** Call `lookup_health_fact` from any MCP client (Claude Desktop, Cursor, the OpenAI Agents SDK) with no API key and no signup, and get a CDC/NIH/USPSTF/SAMHSA-sourced fact, list, or tip with its source link. The full Signal API — sequenced cued-message streams over a 16,500+ library of federally-sourced facts, lists & tips that advance on each patient's response, each with a receptivity score + audience-safety verdict — is a free sandbox key away. Display-mode, no PHI. Not medical advice. Try it → https://uphealth.us/signal/try