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

Annotations already declare readOnlyHint and idempotentHint, so the description adds value by specifying the result is 'based on their primary passport,' clarifying that output is user-specific. It does not disclose return format or edge cases, but the annotation coverage lowers the burden.

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 single, front-loaded sentence with no redundant words. Every phrase adds functional context, and the structure is perfectly scannable.

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 tool with strong annotations, the description sufficiently conveys the core output (country reference info and visa requirement). It doesn't enumerate what 'reference info' includes or behavior without a passport, but the simplicity and annotation support make it mostly complete.

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% with country_code already described as 'ISO country code, e.g. TH.' The description adds no additional parameter meaning, so baseline 3 applies without further credit.

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 provides country reference info and the user's visa requirement based on their primary passport. It distinguishes itself from siblings like get_visa_status and list_visas by focusing on country-level info tied to the user's passport, though it lacks an explicit verb like 'retrieve'.

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: use this tool when you need country reference info or a visa requirement derived from the user's primary passport. However, it does not explicitly say when not to use it or mention alternatives, leaving room for confusion with similar sibling tools.

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