One file, one path: from x = 1 to shipping an async, typed, tested AI service that survives production.

Every example is drawn from the code AI engineers actually write β€” agent loops, tool registries, token streams, Pydantic schemas, FastAPI endpoints, pytest suites. No foo/bar filler.

Companion reads: 🐹 Golang for AI Developers (the sibling to this guide), πŸ—οΈ Building High-Quality AI Agents, πŸ”„ The Agentic Loop Guide, 🏒 Enterprise-Ready AI Agents.

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