loan_comparison

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

With no annotations, the description must carry behavioral disclosure. It does this by stating that invalid loans are reported per-index instead of failing the whole comparison, and it clarifies input compatibility across loan objects. It doesn't discuss side effects, but this is a calculation tool where mutation is unlikely.

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?

Two sentences, each purposeful: the first states the action and result, the second covers input compatibility and error behavior. No filler.

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?

An output schema is present, so return-value details need not be in the description. The description adequately covers the input contract, cross-tool compatibility, and error handling for a moderately complex comparison tool.

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 only gives a generic description for the loans array, but the description specifies the exact fields (principal, rate, time, periods) inherited from financial_calc loan_payment. It also explains error granularity per-index, which adds semantic context to the parameter.

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 opens with a specific verb ('Compare') and resource ('multiple loan options') plus a clear outcome ('identify the lowest monthly payment'). This also differentiates it from sibling financial_calc, which would handle a single loan.

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 clearly frames the tool for multi-loan comparisons, and references financial_calc for field compatibility. However, it doesn't explicitly instruct when not to use it or name financial_calc as the single-loan alternative, so it lacks explicit exclusion guidance.

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