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

Annotations already declare readOnly, idempotent, non-destructive and closed-world behavior, so the safety profile is fully covered. The description adds domain-level context beyond that by explaining how many items come back and how each item is scoped (one home state, 27 comparisons), which shapes how an agent should interpret the results.

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 short sentences, each carrying distinct information: what is listed, what an item represents, and when to call it. The routing instruction is placed last as the call-to-action and there is no redundant restatement of the title.

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 zero-parameter, read-only listing tool with no output schema, the description covers what an agent needs to decide to call it and what the items are. It stops short of indicating what fields come back per version, such as an identifier to pass to a follow-up tool, which leaves a small gap in the selection workflow.

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 tool takes zero parameters, so per the baseline there is nothing the description needs to disambiguate. It correctly stays silent on inputs rather than inventing filtering options that the empty schema does not support.

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 plus the exact scope: 24 versions, each written for taxpayers of one home state in that state's language, each comparing against 27 other countries. That content description implicitly separates it from siblings like list_countries, so an agent can tell what this returns without opening a 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?

Gives an explicit entry-point rule: "Call this first if you are not sure which version fits the user." It is clear guidance for the uncertain-selection case, but it does not say when to skip this tool or name the alternative to use once a version is already known.

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