Tool Design & MCP Integration (D2)
Design tool interfaces, build MCP servers, configure tool choice.
Tool Design & MCP Integration (D2) covers the surface between Claude and the systems it drives: how you describe a tool, what it returns when something goes wrong, and how MCP servers plug into Claude Code and your agents. The exam tests whether you can author tools Claude uses cleanly — and avoid the shapes it misuses.
Expect questions on designing tool interfaces with clear descriptions and boundaries, returning structured error responses from MCP tools, distributing tools across agents and configuring tool choice, integrating MCP servers into agent workflows, and selecting the right built-in tool (Read, Write, Edit, Bash, Grep, Glob) for the job.
This domain spans 5 subtopic areas, covered by 109 practice questions across 26 easy, 56 medium, and 27 hard items.
A customer support agent has two tools: lookup_order_by_id and lookup_order_by_email. Both descriptions say only 'Looks up an order.' The agent frequently calls the wrong tool, passing an email to lookup_order_by_id. What description change most directly fixes the routing failure?
What's covered
Subtopic areas in Tool Design & MCP Integration, drawn from the exam blueprint: