list_countries

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

The description adds that the list includes states/provinces and covers all available countries. Since the annotations already declare readOnlyHint=true and openWorldHint=false, this is additional context but does not cover pagination, return structure, or other edge-case behaviors. No contradiction with annotations.

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 two sentences long, with the main action in the first and a practical use case in the second. No wasted words, and the most important information is front-loaded.

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 list tool with one optional parameter and no output schema, the description adequately conveys what is returned (countries with states/provinces) and when to use it. The annotations and schema handle the rest, so it is complete enough for an agent to invoke correctly.

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 input schema provides a complete description of the 'fields' parameter, including its default value. The description itself does not elaborate on parameter usage, but the schema fully covers it, so the baseline 3 is appropriate.

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 lists all countries available in WooCommerce, including states/provinces. The verb 'list' and specific resource 'countries' make its function obvious, distinguishing it from sibling tools like list_currencies or list_shipping_zones.

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 a clear use case: setting up shipping zones and tax rules. However, it does not mention alternative tools or exclusion criteria, so it falls short of explicit when-not-to-use guidance.

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