cosine

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

With no annotations, the description carries the burden and discloses important behavior: input in degrees, result range [-1, 1], logging of operation and result, and a Dict return containing either result or error. It doesn't detail error cases or side effects beyond logging, but those are secondary for a pure math operation.

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?

Purpose is front-loaded in the first sentence, and the remaining Args/Returns/Notes lines each add a non-redundant constraint: units, result range, return shape, and logging behavior. No filler or excessive detail.

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 single-parameter math tool, the description covers invocation (what object to pass), units, expected output range, return format, and side effect (logging). The output schema also exists, so the missing detailed return shape is not a gap.

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 0%, so the description compensates by explaining the data parameter as 'an object containing the angle in degrees' and by clarifying angle units. It does not spell out the exact JSON shape (data.angle), but the schema's AngleOperation definition fills that gap.

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?

Opens with a specific verb and object: 'Calculate the cosine of an angle in degrees.' This distinguishes it from sibling math/trig tools (sine, tangent) and states the unit, so an agent knows this is the cosine operation and not a generic angle calculator.

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 first line and Notes give clear context for when to use it: whenever the cosine of an angle expressed in degrees is needed, with a reminder that radians are not accepted. It does not explicitly contrast with sine/tangent siblings, but the wording is unambiguous enough for selection.

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