Building a Phone Agent with Patter SDK: Dynamic Variables, Guardrails, Latency Dashboard & Evaluation

The guide builds a restaurant reservation phone agent workflow with Patter SDK. It defines dynamic call variables, registers callable tools for checking availability, booking, hours, and human handoff, and applies output guardrails to each response. Developers can simulate voice-to-text and text-to-speech behavior, run scripted call flows, and track latency and cost metrics on the dashboard. A deterministic evaluation framework validates the agent, and the same logic maps to a real deployment with Twilio and OpenAI Realtime. For voice agent developers, this end-to-end example from prototype to production is particularly useful, with output guardrails and latency monitoring enhancing user experience.