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

Since no annotations are provided, the description carries the full burden of behavioral disclosure. It discloses a key edge-case behavior (trips without a rate are listed with reason, not dropped) and includes the cryptic 'Never metered' note, which likely indicates no rate-limit impact. It does not explicitly state read-only behavior, but that is implied for a summary tool. No contradictions with annotations (none present).

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 two sentences with no filler. It front-loads the purpose, lists the output components, includes a crucial edge-case behavior, and states defaults. Every sentence earns its place, making it efficient and easy to parse.

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 lack of an output schema, the description sufficiently explains what the tool returns (trips, distance kept per unit, rate per trip, deductible amount per currency). It also covers the edge case of trips without rates, states defaults, and is concise enough for an agent to call it correctly. No critical missing information is apparent.

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%, meaning all parameters (to_date, category, from_date) are already documented in the schema with their defaults and allowed values. The description adds minimal new semantic value—it reiterates the default calendar year (already in schema) and mentions 'per category' which is also in the schema. Baseline of 3 is appropriate given high schema coverage.

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 function: summarizing deductible mileage for a date range, broken down by category, with specific metrics (trips, distance, rate, deductible amount). It also includes behavioral details like 'Trips with no applicable rate are listed with the reason, not silently dropped' and 'Never metered,' which distinguish it from siblings like trip_list or mileage_export. The verb 'summarize' is implicit but the scope and output are specific.

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 provides clear context about defaults (current calendar year) and what the tool does, but it does not explicitly contrast with sibling tools or state when to use this versus alternatives like trip_list or mileage_export. Usage is implied rather than explicitly guided, with no 'when-not-to-use' or alternative recommendations.

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