add

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description clearly states the pure computation of a sum, which is the primary behavior. It does not mention edge cases or return type, but for such a trivial operation, the disclosed behavior is adequate and not misleading.

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 sentence that is front-loaded and directly states the operation. Every word earns its place, and there is zero waste.

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 two-number addition tool with complete parameter schema, the description sufficiently covers the tool's purpose. It doesn't explicitly state the return value, but that is self-evident from the operation. The low complexity and high schema coverage make the description complete enough.

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 100%, with both parameters 'a' and 'b' described as addends. The description does not add any extra meaning beyond the schema, so the baseline score of 3 applies.

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 '计算两个数的和' clearly states the tool computes the sum of two numbers. It uses a specific verb and resource, and naturally distinguishes itself from siblings subtract, multiply, and divide by describing the addition operation.

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 use when addition is needed, but it does not explicitly state when to use or not use this tool versus the sibling operations. The context is clear from the name and sibling names, but explicit guidance is absent, so it falls to the 'implied usage' level.

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