# Practical ways to use the Claude Agent SDK 💰 Track agent costs per step and per model to optimize your budget. Cost and Usage Tracking uses `total_cost_usd` and `modelUsage` to monitor token consumption and costs in real time. 📌 Title: Cost and Usage Tracking 🔗 URL: 🧩 Overview ` gives cumulative estimated cost per call. `modelUsage` breaks down tokens by model. Prompt caching optimization can significantly reduce costs. 🛠 How to use it Read `total_cost_usd` from `ResultMessage`. Deduplicate using `AssistantMessage` IDs for accurate per-step accounting. 🏗 Practical usage - Monitor `total_cost_usd` per `query()` call and trigger alerts when thresholds are exceeded. - Use `modelUsage` to break down costs between sub-agent Haiku and main Opus usage, visualizing where costs concentrate. - Set `ENABLE_PROMPT_CACHING_1H=1` to extend TTL from 5 minutes to 1 hour, preventing cache misses across many short sessions. - Accumulate `total_cost_usd` across multiple `query()` calls for session-level cost management. 💡 Use cases 📊 Per-step cost visualization dashboard 🔔 Automatic budget threshold alerts ⚡ Prompt cache optimization for cost reduction ⚠️ Watch out `total_cost_usd` is an approximate estimate. Use the Usage and Cost API / Console for authoritative billing. The SDK doesn't provide session totals — accumulate on the app side. #ClaudeAgentSDK# #AI#