Tool Design & MCP Integration
Key terms and definitions for Domain 2. Each entry includes a concise definition, exam context, and links to the relevant lesson.
10 of 10 terms
inputSchema
The JSON Schema object within a tool definition that specifies the structure, types, and constraints of the tool's input parameters. Follows standard JSON Schema with properties, required fields, and descriptions.
Exam Context
Always mark required parameters explicitly. Use description fields on every property. Constrain with enum, minimum, maximum, and pattern where appropriate.
MCP Client
A component that connects to one or more MCP servers, discovers their capabilities, and makes them available to the LLM. The client manages the lifecycle of server connections and translates between the MCP protocol and the LLM's tool format.
Exam Context
Understand that a single client can connect to multiple servers simultaneously. The client aggregates tools from all connected servers into a unified tool list for Claude.
MCP Server
A process that exposes tools, resources, and prompt templates over the Model Context Protocol. MCP servers can be implemented in any language and communicate via stdio or HTTP (SSE) transport.
Exam Context
Know the three capability types: tools (executable actions), resources (data sources), and prompts (templates). Understand that servers declare capabilities during initialization.
MCP Transport
The communication layer between MCP clients and servers. Two standard transports: stdio (local processes communicating via stdin/stdout) and HTTP with Server-Sent Events (remote servers). Stdio is simpler; HTTP enables remote deployment.
Exam Context
Stdio is the default for local tools. HTTP+SSE is required for remote or shared servers. Know the tradeoffs: stdio has no network overhead but requires local execution.
Prompt Template
An MCP capability that provides reusable prompt structures. Servers expose prompt templates with defined arguments that clients can fill in. Useful for standardizing interactions across different clients.
Exam Context
Prompt templates are the third MCP capability alongside tools and resources. They enable server-defined interaction patterns that clients can discover and use.
Resource
An MCP capability that exposes data to the LLM. Unlike tools (which perform actions), resources provide read-only access to content like files, database records, or API responses. Resources have a URI and return text or binary content.
Exam Context
Distinguish resources from tools: resources are for reading data, tools are for performing actions. Resources are identified by URI patterns.
Tool Approval
A mechanism for requiring user confirmation before a tool executes. Configured through permission settings that classify tools as allowed, denied, or requiring approval based on the tool name or server.
Exam Context
Know how to configure tool permissions in Claude Code. Understand the difference between allowedTools (whitelist) and tools that require explicit user approval.
Tool Error Handling
The practice of returning structured error information from tools so Claude can understand what went wrong and attempt recovery. Tool results should include is_error: true and a descriptive message rather than throwing exceptions.
Exam Context
Never throw unhandled exceptions from tools. Return errors as structured content so Claude can reason about them. Include actionable information in error messages.
Tool Schema
A JSON Schema definition that describes a tool's name, purpose, and input parameters. Claude uses the schema to understand what the tool does and how to construct valid inputs. Well-designed schemas include clear descriptions and constrained types.
Exam Context
Schema quality directly affects tool selection accuracy. Include descriptions on every parameter. Use enums to constrain values. Avoid overly complex nested schemas.
Tool Selection
Claude's process of choosing which tool to invoke based on the user's request and available tool schemas. Affected by tool names, descriptions, parameter schemas, and system prompt guidance.
Exam Context
Tool names and descriptions are the primary signals for selection. Avoid ambiguous or overlapping tool names. Use the system prompt to provide tool selection guidance when needed.