loan_comparison

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

The annotation 'readOnlyHint: true' already indicates this is a safe read operation with no side effects. The description adds useful context about what the tool calculates (total cost, monthly payment, true APR) and the decision-making scenarios, but doesn't disclose additional behavioral traits like computational complexity, error handling, or output format details. With annotations covering the safety profile, a 3 is appropriate as the description adds some value beyond annotations.

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 perfectly concise and well-structured. Two sentences total: the first states the core purpose and metrics, the second provides usage scenarios. Every word earns its place with zero redundancy. It's front-loaded with the most important information (what the tool does) followed by context (when to use it).

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 complexity (7 parameters, financial calculations), the description provides complete context. It explains what the tool compares and when to use it. With annotations covering safety (readOnlyHint: true), 100% schema coverage documenting all parameters, and an output schema existing (though not shown), the description doesn't need to explain return values or parameter details. It focuses appropriately on the tool's purpose and usage scenarios.

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 100%, with all 7 parameters well-documented in the schema (e.g., 'Amount to borrow', 'Annual interest rate for option A (%)'). The description doesn't add any parameter-specific information beyond what's in the schema. According to guidelines, when schema coverage is high (>80%), the baseline is 3 even with no param info in the description, which applies here.

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: 'Compare two loan options by total cost, monthly payment, and true APR.' It specifies the verb ('compare'), resource ('two loan options'), and key comparison metrics. It also distinguishes from siblings like 'mortgage_calculator' (single loan) and 'debt_payoff_plan' (repayment strategy) by focusing on comparative analysis between two options.

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 explicitly provides usage guidance: 'Helps decide between a lower rate with higher fees vs higher rate with lower fees, or shorter term (higher payment, less interest) vs longer term (lower payment, more interest).' This gives clear scenarios for when to use the tool, including trade-off decisions. It implicitly distinguishes from siblings like 'compound_interest' (growth) and 'rent_vs_buy' (housing decision).

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