Get a complete list of countries for any continent using its standard code. Input a continent code (AF, AN, AS, EU, NA, OC, SA) to retrieve all countries in that region.
List every country on a continent.
| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes | Continent code: AF, AN, AS, EU, NA, OC, SA |
Changes observed during successful MCP inspections.
v0.1.3Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The readOnlyHint annotation already covers the read-only behavior, so the description doesn't need to restate it. It adds the behavioral assertion 'every country', indicating an exhaustive, unpaginated list, which is useful beyond the annotation.
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?
Single sentence, six words, directly states the action and scope with no filler.
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 1-parameter list tool, the description fully explains the purpose. The lack of an output schema is mitigated by the straightforward nature of returning a list of countries; nothing else is needed.
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 fully describes the one parameter with allowed values in its description, so the tool description adds no extra semantic value. Baseline 3 is appropriate since schema coverage is 100%.
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 uses a specific verb ('List') and resource ('every country on a continent'), clearly distinguishing it from siblings like country_states (states within a country) and continent (continent details).
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 clearly implies the use case (fetching countries for a given continent) and the required code parameter provides a direct trigger. It doesn't explicitly mention alternatives or exclusions, but the context is unambiguous for this simple listing tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.