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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior, so the safety profile is covered. The description adds useful behavioral context by saying the result contains names and codes and that a code can narrow search_packages through regionCode, though it does not discuss pagination or response shape beyond that.

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 a compact sentence plus a short read-only note, with the core resource and downstream connection front-loaded. There is minimal waste, and the redundant read-only note is small.

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 simple one-parameter lookup with rich annotations, complete schema coverage, and no output schema, the description supplies the essential input context and mentions the returned names/codes. It could be slightly more complete about whether regions and cities are returned as a flat list or nested, but no major call-blocking gap remains.

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 the countryCode parameter is already fully documented as a two-letter code listed by get_countries. The description adds little parameter-specific detail beyond saying the tool operates on one destination country, so the baseline of 3 is appropriate.

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 and resource: it lists regions and cities of one destination country, including names and codes. It also distinguishes the output from get_countries and links the resulting code to search_packages via regionCode.

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 gives clear context that this is a per-country lookup whose codes feed search_packages' regionCode parameter. It does not explicitly say when to use this instead of get_countries or search_inspirations, though the schema supplies the get_countries prerequisite.

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