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

No annotations are provided, so the description carries the burden. It explicitly says 'Reads only,' which is a strong safety disclosure. It also discloses ordering ('oldest first'), the exact fields returned, and the pricing behavior (earnings under the rate in force on its day, or the plain reason it is unpriced). This goes well beyond a generic 'list trips' and gives the agent a clear model of what the tool does and what it returns.

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 with zero waste. The core action and ordering are front-loaded, the return fields are listed compactly, and the filter capability is stated in a short final sentence. Every clause earns its place.

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?

For a read-only list tool with no output schema, the description is nearly complete: it states ordering, fields, pricing behavior, and filters. The only minor gap is that it doesn't describe pagination or result limits, but for a mileage log list this is a small omission. The read-only annotation absence is compensated by the explicit 'Reads only' statement.

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%, so the schema already documents all three parameters with formats and meanings. The description adds the filter dimensions ('Filter by date range and category') but does not add syntax or format details beyond what the schema provides. Baseline 3 is appropriate because the schema does the heavy lifting and the description doesn't need to compensate.

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 states a specific verb ('List trips'), a clear resource ('the mileage log'), and a precise scope: oldest first, with the fields returned and the pricing behavior. It also distinguishes itself from siblings by noting it is read-only and by naming the filter dimensions (date range and category), so an agent can tell it apart from mileage_summary, mileage_export, and trip_add without opening schemas.

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 implies when to use this tool: when you need a chronological list of trips with per-trip earnings and filters. It does not explicitly name alternatives or exclusions, but the read-only note and the filter semantics provide enough context to select it over trip_add, trip_remove, rate_set, and mileage_summary. A small gap is that it doesn't explicitly say 'use mileage_summary for totals' or 'use mileage_export for file output,' but the context is clear.

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