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

With no annotations present, the description carries the full disclosure burden and does well: it explains the rate-selection rule (government-furnished automobile switches standard to reduced rate), the fallback to today's date, and exactly what the response contains including rounding to the nearest cent. It stops short of explicitly stating this is a pure computation with no side effects.

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?

Front-loaded with the core purpose, then conditional rules, then defaults and return shape — a logical order with little waste. The first line largely duplicates the title, a minor redundancy for an otherwise tight paragraph.

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?

There is no output schema, yet the description specifies the returned fields (rate category, rate, effective date, rounded amount), and it covers default behavior and conditional rate logic. An agent has everything needed to call it correctly and interpret the result.

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 coverage is 100%, so baseline is 3; the description adds genuine meaning by explaining the semantic consequence of government_vehicle_available (determines standard vs reduced rate) and that the date drives effective-rate selection. It does not restate the numeric bounds, which the schema already covers.

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?

States a specific verb and resource ('Calculate POV mileage reimbursement', 'using the official GSA rate in effect on the travel date') and enumerates the supported categories. It is clearly distinguishable from sibling rate-lookup tools like get_mileage or get_fleet_rates_by_sin, which retrieve data rather than compute an amount.

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?

It explains what inputs are needed and the conditional logic for automobile travel, so usage is implied clearly, but it never names an alternative tool or states when not to use this one (e.g., when to look up rates via get_mileage instead of computing).

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