List available country codes for Self protocol exclusions

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

Annotations already provide readOnlyHint=true, so the agent knows this is a safe read operation. The description adds useful context about the return format ('ISO 3166-1 alpha-3 country codes with their names'), which isn't covered by annotations. However, it doesn't mention pagination, rate limits, or authentication requirements beyond what annotations imply.

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?

Two sentences with zero waste. First sentence states purpose and context, second sentence specifies return format. Every word earns its place, and the most important information (what the tool does) 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?

Given this is a simple read operation with readOnlyHint annotation, 100% schema coverage, and an output schema (implied by context signals), the description provides exactly what's needed. It explains what the tool returns without needing to detail parameters or safety concerns that are already covered elsewhere.

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 description coverage is 100%, so the schema already fully documents the single optional 'search' parameter. The description doesn't add any parameter-specific information beyond what's in the schema. With high schema coverage, the baseline score of 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 verb ('List') and resource ('available country codes'), specifies the context ('for exclusion in Self protocol'), and distinguishes from siblings by focusing on country codes rather than documentation, configuration, or verification tools. It provides specific format information ('ISO 3166-1 alpha-3 country codes with their names').

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 context ('for exclusion in Self protocol') but doesn't explicitly state when to use this tool versus alternatives. No guidance is provided about prerequisites, timing, or specific scenarios where this tool is preferred over other country-related operations (though none exist in siblings).

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