Anthropic. Hannah Moran and Jeremy Hadfield from Applied AI walking through how to phrase tool calls and agent prompts on a real Pokemon-playing agent — when to push behavior into the system prompt versus the tool description, what the model needs to know about each tool's preconditions. Useful immediately after you write your first MCP server and find Claude calling it in unexpected ways.
Treat the demo game as a teaching surface, not the point. The transferable lesson is prompt/tool contract design; validate any production prompt with eval cases that include wrong-tool and missing-parameter failures.
Decide which behavior belongs in the system prompt, tool description or tool precondition.
Have built or inspected at least one tool-using agent.
Continue through the same learning path with the next curated companion videos.