cos

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

No annotations are provided, so the description carries full burden. It only states what the tool does (calculates cosine) and the input format (radians). It lacks behavioral details such as error handling (e.g., for invalid inputs), performance characteristics, or output format. For a mathematical function with no annotation coverage, this is a significant gap in transparency.

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 and front-loaded: a single sentence that directly states the tool's function and input requirement. There is no wasted text, and every word earns its place by providing essential information efficiently.

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 low complexity (a basic mathematical function), no annotations, no output schema, and one parameter, the description is minimally adequate. It covers the core purpose and input unit, but lacks details on output format, error cases, or usage context. For such a simple tool, this is acceptable but leaves room for improvement.

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 0%, so the description must compensate. It adds meaning by specifying that the 'angle' parameter should be in radians, which is crucial semantic context not in the schema. However, it doesn't explain the parameter's name, range, or units beyond 'radians', leaving some ambiguity. With one parameter and partial compensation, a baseline 3 is appropriate.

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: '计算角度的余弦值' (calculates the cosine of an angle). It specifies the input unit (radians) and distinguishes it from potential degree-based alternatives. However, it doesn't explicitly differentiate from sibling trigonometric functions like 'sin' or 'tan', which is why it doesn't reach a perfect score.

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 mentions the input is in radians, but doesn't specify scenarios where cosine is appropriate over other trigonometric functions or mathematical operations available in the sibling list. There's no mention of prerequisites, limitations, or comparison to similar tools.

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