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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description still adds real behavioral value beyond them: the exact count (8), the meaning of the status values including the preview_not_in_force case, and that no arguments are taken. It does not discuss pagination or caching, which is a minor remaining gap for a fixed small list.

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?

Three sentences with no filler: content and scope first, then the decision rule, then the routing alternative. Every sentence earns its place and nothing needs to be re-read.

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?

Output schema exists, so return structure need not be explained. Combined with annotations covering the safety profile, the description supplies everything an agent needs: what it returns, the status vocabulary, when to pick it, and where to go for depth.

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?

Zero parameters, so the baseline is 4. The description reinforces this with 'Takes no arguments,' matching the empty schema and additionalProperties=false, leaving no ambiguity about invocation.

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 ('List every country Civica covers') and quantifies scope ('currently 8'), then enumerates what each entry contains. The closing sentence explicitly distinguishes it from get_track_info, so an agent can separate the two siblings without opening either schema.

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?

Explicitly names the triggering condition ('Use this first when the country is not yet known or you need to check whether a country is supported') and names the alternative with its own condition ('For depth on one country use get_track_info instead'). This is a clean when/when-not/alternative triad.

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