Add two numbers

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

No annotations are provided, so the description carries the behavioral burden. It states that this is a pure computation: it adds the two numbers and returns the sum, with no mention of side effects or external state. It does not discuss numeric edge cases, but none are particularly relevant for a simple addition 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?

The description is two short sentences with no wasted text. The first sentence states the complete behavior and return value, and the second adds a useful usage directive. It is front-loaded and easy to parse.

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 two-parameter arithmetic tool, the description covers the operation, the inputs, and the return value. No output schema exists, but 'returns their sum' is enough to describe the successful outcome. The tool is simple enough that 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?

The input schema provides only names and number types, with no descriptive text. The description says 'two numbers' and 'their sum,' which maps to the a and b parameters and clarifies that both are operands in the addition. This is adequate for such a simple case, though it does not add deeper individual-parameter details.

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 operation ('Adds two numbers') and the result ('returns their sum'), using a specific verb-resource form. It is immediately distinguishable from the sibling tools, which are unrelated (say_hello, echo, get_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?

It gives an explicit usage directive: 'Prefer this over doing arithmetic yourself.' It does not name any alternative tool, but none of the siblings are arithmetic-related, so there is no real alternative to distinguish. The guidance is sufficient for such a simple operation.

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