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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool returns a record, implying a read-only operation, but does not describe pagination, output format, or error behavior. The description's simplicity is adequate for a look-up tool, but it lacks explicit statements about side effects (e.g., none) or rate limits, though the nature of the tool suggests none are likely.

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, short sentence with no filler. It is extremely concise and front-loads the essential purpose. Every word earns its place, achieving maximum efficiency.

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 the tool's simplicity (no required parameters, no output schema), the description is minimal but sufficient to understand the core function. However, it doesn't explain why 9 parameters are accepted for a simple record lookup, nor does it clarify that parameters are discarded (as the schema suggests individual params are). This ambiguity could confuse an agent about what the tool actually does with all those parameters.

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 schema description coverage is 100%, so the schema already documents all 9 parameters thoroughly. The description adds no extra meaning beyond the schema; it only mentions the concept of a record for BT, which does not clarify parameter usage. Baseline 3 is appropriate because the schema does the heavy lifting.

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 identifies the tool as returning a public ISO 3166-1 record for the country code BT. This is a specific, unambiguous resource and action, easily distinguished from the many sibling tools that handle URLs, files, or search queries.

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 provides no guidance on when to use this tool versus alternatives. It does not mention that it is for country-code lookups only, nor does it point to related tools like 'timezone' or 'geo-hint' for location-based data. An agent would have to infer its usage from the ISO reference in the description.

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