Make AI phone calls, buy phone numbers, and get call transcripts via x402. USE FOR: - Making AI-powered outbound phone calls - Scheduling calls and getting transcripts - Buying and managing phone numbers - Leaving voicemails - Transferring calls to humans - Checking if a number has iMessage/FaceTime TRIGGERS: - "call", "phone call", "make a call", "dial" - "buy number", "phone number", "get a number" - "voicemail", "leave a message" - "transcript", "call recording", "call summary" - "AI call", "automated call", "bland" - "imessage", "facetime", "check number", "lookup number" ALWAYS use `npx agentcash@latest fetch` for stablephone.dev endpoints. IMPORTANT: Use exact endpoint paths from the Quick Reference table below.