This is the Rust SDK itself, not an MCP server implementation. It provides a framework for building MCP servers. The two 'tools' (adder, empty) are minimal example/test tools in the conformance test suite, not representative of production tool design. The SDK demonstrates solid infrastructure (multiple transports, auth, elicitation, request-state support), but the sample tools are demonstrably poor quality: 'empty' tool has zero meaningful description, 'adder' description is extremely terse (20 chars, at the floor of acceptability), and neither tool's parameter descriptions provide contextual guidance for LLM selection or usage. The tools appear to be testing artifacts rather than production examples. Evaluating the SDK by these sample tools is inappropriate, however, the rubric requires assessment of visible tool definitions, and these are the only explicit tool registrations visible in the provided source.

• Expand 'adder' description to 50-150 chars: 'Add two integers together. Use when you need to compute the sum of two numbers. Returns the integer result.' Include usage context.
• Replace 'empty' tool with a meaningful example, or remove it entirely. If testing a no-op, use an internal test fixture, not an exposed tool.
• Add parameter descriptions to 'adder' that specify type constraints: 'left operand (integer, range: -2147483648 to 2147483647)' and 'right operand (same range)'.
• Document output schemas for both tools: 'adder returns {"result": integer}'; 'empty returns {}' (if kept).
• Add error handling examples: 'If input is not an integer, returns error code INVALID_INPUT with message: "Expected integers, got: <type>".'
• If these are intentionally test/conformance tools, move them to a separate 'examples' namespace and document that they are not production patterns. Provide a canonical production example tool with complete definitions.

Inferred effective spec: 2026-07-28+.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry