BuildMcpServer

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It describes the basic behavior (addition) and return value (sum), but doesn't mention potential constraints like numeric limits, error handling for non-numeric inputs, or performance characteristics. For a simple arithmetic tool, this is adequate but minimal.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is perfectly structured and concise: a clear purpose statement followed by well-organized Args and Returns sections. Every sentence earns its place, with no wasted words or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity (basic arithmetic), the description is complete: it states the purpose, parameters, and return value. The output schema exists (though not shown), so the description doesn't need to explain return values further. For this context, nothing essential is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It provides clear semantic meaning for both parameters ('First number', 'Second number') beyond the schema's generic titles ('A', 'B'), though it doesn't specify numeric types or ranges. For a 2-parameter tool with no schema descriptions, this adds good value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose with a specific verb ('Add') and resource ('two numbers'), and it distinguishes from sibling tools (divide, multiply, subtract) by specifying the exact arithmetic operation. The opening sentence 'Add two numbers together' is unambiguous and complete.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states when to use this tool ('Add two numbers together'), and the context of sibling tools (divide, multiply, subtract) makes it clear this is for addition versus other arithmetic operations. No explicit exclusions are needed for such a simple, distinct tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.