What problem does it solve? Building against the Terra API Models endpoints involves per-model response shapes, non-obvious result semantics (unsupported devices return HTTP 200, not errors), and per-run billing that charges even for failed runs. This Skill gives an AI agent the exact guidance needed to call the models correctly and interpret results without wasting credits. ## Core Features & Use Cases - Model catalog and run workflow: Covers the three generally-available models (sleep_window, cycle_phase_tracker, graph_impute), the GET /v2/models and GET /v2/models/run endpoints, authentication headers, and the extra table parameter Smart Fill requires. - Result-handling guidance: Explains how to distinguish unsupported-device responses (HTTP 200 with unsupported: true) from genuine 4xx/5xx errors, handle no_data cases, and read per-model fields like reported vs computed in Smart Fill output. - Pricing and boundaries: Documents the $0.01 per-run credit model, the 30-day run log retention, and the boundary with the Unified API for connecting users. - Use Case: You are building a sleep-coaching feature and need to call GET /v2/models/run?model=sleep_window for a connected user, then correctly render the recommended bedtime, consistency score, and top recommendation while handling users whose devices are unsupported. ## Quick Start Ask your agent to run the Terra API sleep_window model for a connected user over a date range and explain how to handle an unsupported-device response.