medium★ EssentialAnthropic OpenAI Microsoft

What is the Model Context Protocol (MCP), and how do you design good tools for an agent?

MCP standardized how agents plug into tools and data, but tool design is what makes or breaks reliability. The signal is knowing what MCP actually standardizes and the principles behind a tool the model can call correctly from its description alone.

Updated Aug 2026 · Grounded in real Applied AI Engineer interview loops and written to a senior-engineer editorial bar.

more free answers with an account · no card

LEARN THE BACKGROUND

These lessons teach the material this question tests, in order and from the beginning.

Agent Engineering·Tools as an interfaceFree14mDesigning an API for a consumer that cannot read the docsA tool set is an API whose only user is a model with no memory of your codebase and no way to ask. That constraint changes granularity, naming and error design in specific ways, and most tool sets are built as though a person were reading them.Applied AI Engineering·Tools and your first agentSign in14mTool design is prompt engineering by another nameThe model chooses tools using only their names, descriptions and parameter schemas. That surface is the whole prompt for the decision, which makes tool design an authoring problem rather than an API problem, and explains most wrong-tool bugs.

UP NEXT ON YOUR JOURNEY

Next in this trackWhat is agent reflection / self-correction, and does it actually improve agent performance?Next in this trackCompare chunking strategies (fixed-size, recursive, semantic, parent-child). How do you pick?Next in this trackHow do you implement citations and source attribution in a RAG system, and why does it matter?

DISCUSSION · 0

No comments yet — be the first to share your approach.