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

The description discloses the function's behavior and its return value ('Returns sum'). For a pure arithmetic operation, this is fully transparent. No additional behavioral traits like side effects or permissions are relevant.

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 extremely concise, using brief statements for the operation, parameters, and return value. Every element serves a purpose with no extraneous text.

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, the description is complete. It covers the operation, parameters, and return value, and no output schema is needed to understand the result.

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 description lists 'a: int' and 'b: int', which simply repeats the input schema's type information without adding semantic meaning beyond labeling them as numbers. The schema coverage is 0%, so the description does not compensate for the lack of parameter descriptions.

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 'Function to add two numbers' which clearly identifies the verb (add) and resource (two numbers). It is specific and unambiguous, though it doesn't need to differentiate from siblings as none exist.

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 doesn't explicitly state when to use this tool, but the phrase 'Function to add two numbers' implies the use case is whenever addition is needed. There are no alternatives or exclusions mentioned, which is acceptable given the simplicity of the function.

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