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

With no annotations provided, the description carries the full burden of behavioral disclosure. It fails to state whether this is a pure computation, whether it requires any authentication, or how errors are handled. It also lists parameters that do not appear in the schema, creating confusion about invocation 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 compact and front-loads the core purpose in the first sentence. The second sentence lists inputs but is under-specified and conflicts with the schema, slightly reducing its value. Overall, it is appropriately sized with no redundant content.

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?

The tool has no output schema, no annotations, and a confusing parameter situation. The description does not clarify how inputs should be passed, what the formula assumptions are (e.g., market vs book values), or what a typical response looks like. An agent cannot reliably call this tool correctly based on the available information.

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 declares zero parameters, yet the description instructs the user to provide equity, debt, costEquity, costDebt, and optional taxRate. This is a direct contradiction with the input schema and makes the parameter information misleading. The description provides names only, with no types, formats, or full required/optional semantics beyond taxRate.

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 uses a specific verb 'Calculate' with a clearly defined resource, Weighted Average Cost of Capital, and specifies the output unit (percentage). This distinguishes it from the many sibling financial tools, as WACC is a unique and well-defined calculation.

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 the tool should be used when calculating WACC but offers no explicit guidance on when to choose this tool over alternatives, nor any exclusions or context about when not to use it. The usage context is inferred solely from the purpose statement.

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