list_countries

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

Without annotations, the description adds some behavioral context: notes a custom 900+ block and mentions a 7-day cache. However, it does not explain what the custom block means or detail other traits like authentication or output format.

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 extremely concise: one sentence with two key pieces of information. Every word is essential, with no wasted verbiage.

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 zero parameters, no output schema, and no annotations, the description provides the core purpose and two behavioral notes. It is adequate but could be more complete by clarifying the custom block or expected output.

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 has no parameters (100% schema coverage), so the description need not add parameter details. Baseline 4 applies as no compensation is required.

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 it lists manufacturer/origin countries, with a verb and resource. However, it does not explicitly differentiate from sibling tools like list_colors or list_categories, though the unique context is implied.

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 lacks context such as prerequisites or exclusions, leaving the agent without decision support.

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