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

No annotations are provided, so the description must disclose behavior. It states that the tool adds two numbers and returns the sum, which accurately conveys the core behavior. It does not mention edge cases (e.g., handling of negative numbers or precision), but for a pure arithmetic function these are implicit and unlikely to lead to misuse.

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 a single, front-loaded sentence with no filler or redundant information. It efficiently states the operation and the return value, making it easy to read and understand at a glance.

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 simple tool that adds two numbers and returns the sum, the description fully covers the operation, the required inputs (implicitly), and the output. There is no output schema, but the description explains the return value. No additional information is needed for an agent to call the tool correctly.

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 says 'two numbers' but does not explicitly refer to the parameter names 'a' and 'b' or specify which parameter corresponds to which operand. Since schema description coverage is 0%, the description could add more clarity, but because addition is commutative, the lack of specific mapping is not a functional gap. It adds minimal semantic value beyond the schema's type declarations.

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 verb ('adds') and a clear resource ('two numbers') with an explicit result ('returns the sum'). It is immediately distinct from the sibling tools echo and server_time, which serve other purposes, so there is no ambiguity about what this tool does.

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 implies when to use the tool (whenever addition of two numbers is needed) and there is no competing tool for this operation. It does not explicitly state alternatives or exclusions, but given the simplicity and lack of similar siblings, the usage context is clear without further guidance.

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