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. While '计算两个数字的和' implies a read-only calculation operation, the description doesn't explicitly state whether this is a safe operation, what happens with invalid inputs, or any performance characteristics. For a tool with zero annotation coverage, this is insufficient behavioral context.

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 - a single sentence that directly states the tool's purpose without any unnecessary words. It's appropriately sized for this simple mathematical operation and gets straight to the point with 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 addition tool with 2 parameters, 100% schema coverage, and no output schema, the description is minimally adequate. It tells what the tool does but lacks information about return values, error handling, or edge cases. Given the tool's simplicity, the description is complete enough to understand the basic operation but could provide more context about the result format.

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 description coverage is 100%, with both parameters 'a' and 'b' clearly documented as '第一个数字' and '第二个数字' (first number, second number). The description adds no additional parameter information beyond what's already in the schema. According to the scoring guidelines, when schema coverage is high (>80%), the baseline is 3 even with no param info in the description.

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 tool's purpose as '计算两个数字的和(加法)' which translates to 'calculate the sum of two numbers (addition)'. This is a specific verb+resource combination that tells exactly what the tool does. However, since there are no sibling tools, the description doesn't need to distinguish from alternatives, so it doesn't reach the highest score of 5.

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 provides no guidance on when to use this tool versus alternatives. It simply states what the tool does without any context about appropriate use cases, prerequisites, or limitations. This is a basic description that lacks usage instructions.

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