Building an Agentic Personal Trainer - Part 3: The System Prompt
Tools give the agent capabilities but the system prompt gives the agent its personality. Getting the tone right—in this case "coach, not drill sergeant"—requires iteration, opinion, and intuition, not just correct syntax.
Building an Agentic Personal Trainer - Part 1: Architecture and Philosophy
After building an [autonomous stock trading system](https://www.mosaicmeshai.com/blog/building-an-mcp-agentic-stock-trading-system-part-1-the-architecture) with custom MCP servers, I wanted something different: a conversational AI that collaborates rather than executes. Something that asks "how are you feeling?" before suggesting a workout.