cos

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

No annotations provided, and the description gives no behavioral details beyond 'Compute cosine.' It does not mention domain, range, error handling, or precision behavior.

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 very concise (two words), but it sacrifices completeness. It is front-loaded but lacks structure and fails to elaborate on core information.

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 mathematical tool, the description is barely adequate. The schema clarifies parameter units, but no output schema or sibling differentiation is provided. Overall, it meets minimum viability but has gaps.

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 input schema covers both parameters with descriptions ('Number (in radians)' for x, 'Optional precision' for precision). The description adds no additional meaning beyond the schema, so 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?

Description is 'Compute cosine,' which is a tautology because it restates the tool name 'cos'. It does not distinguish from sibling tools like cosh, acos, or other trig functions.

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?

No guidance on when to use this tool versus alternatives (e.g., acos for inverse, cosh for hyperbolic cosine). The description offers no usage context.

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