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

Annotations already declare read-only, non-destructive, closed-world behavior, and the description adds genuinely new operational context: the ranking criteria (distance, fit with interests/periods, fame), the straight-line distance metric, the deliberate omission of travel times with the reason, and the coverage constraint ('Only covered cities are listed'). These are exactly the caveats an agent needs to interpret results correctly.

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 resource and scope, followed by example queries, then ranking/metric caveats. Four sentences, none redundant, and the limitations are placed after the core definition rather than buried.

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?

With no output schema, the description still conveys what comes back ('lists what to see there in one day', ranked) and flags the two things that could mislead an agent: straight-line distances without travel times, and the covered-cities-only restriction. Nothing essential for correct invocation is missing.

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 86%, so the schema already carries the parameter burden and baseline is 3. The description reinforces the role of interests and periods in ranking and clarifies that distances are straight-line (relevant to max_distance_km) and that the output is a one-day selection (relevant to hours_on_site), but adds no format or range detail beyond that.

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 ('Day trips from a base city to other covered cities and towns nearby') and pins the scope to destination-level cities, which separates it from attraction-level siblings like find_nearby_attractions. Example queries ('day trips from Florence', 'a day trip from Munich for castles') make the intent unmistakable.

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 example phrasings give clear situational context for when to reach for this tool, and 'from a base city' establishes the required anchor. It does not explicitly name alternatives (e.g. recommend_destinations or find_nearby_attractions) or state when not to use it, so routing between siblings still requires inference.

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