countries_visited

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

With no annotations, the description bears the burden of disclosure. It explains the output structure (separate trips, time spent, distinct days, cities) and the country filter, but does not mention default behavior with no parameters, ordering, or edge cases like ambiguous country names. It provides a functional overview but lacks depth.

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 concise (two sentences), front-loaded with the purpose, and every sentence adds value. The example with the country filter is useful without being verbose.

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 no output schema, the description covers the key return elements (trips, time, days, cities) and the filtering behavior. It does not state the default when no country is provided or how the results are structured, but it is sufficiently complete for an agent to select and invoke the tool for common use cases.

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?

The input schema already provides 100% coverage of parameter meanings. The description adds a brief example for the country parameter, but since and until/period semantics are already well-documented in the schema, so minimal added value.

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: it provides country-level travel statistics over a period, including trips, time spent, distinct days, and cities. It also distinguishes itself from siblings like cities_visited and trips by focusing on countries as the aggregation unit.

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 implies usage for country-focused travel queries and gives a concrete example of filtering by country ('how many times have I been to Japan'). However, it does not explicitly contrast with alternatives such as cities_visited or trips, nor does it state when not to use this tool.

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