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

With no annotations provided, the description carries the burden of behavioral disclosure. It accurately describes a pure, side-effect-free operation that returns the sum, which fully covers the observable behavior for a simple arithmetic tool.

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?

A single short sentence contains all necessary information with no filler or redundancy. Every word contributes to understanding the tool's purpose and result.

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?

For a tool with two scalar numeric parameters, no output schema, and no side effects, the description is fully sufficient. An agent can confidently select and invoke this tool based solely on the provided text.

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?

The schema provides only parameter names and types with no descriptions, and the description does not explicitly name a and b. However, the phrase 'two numbers' plus the binary nature of addition reasonably implies that both parameters are operands, providing minimal but sufficient semantic context.

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 states a specific operation—adding two numbers—and the result it returns, the sum. This clearly identifies the tool's function and is immediately distinguishable from the sibling tools echo and server_time.

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 makes the intended usage clear: use this tool whenever two numeric values need to be summed. While it does not explicitly mention alternatives, none of the sibling tools are relevant to arithmetic, so no exclusionary guidance is necessary.

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