bunny_list_countries

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds useful behavioral context by specifying that it lists all countries with ISO 2-letter codes and frames the data as static reference material. This is beyond what the annotations alone convey.

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 concise sentences, each earning its place: the first states exactly what the tool does, the second explains why an agent would need this data. The core action is front-loaded and there is no unnecessary verbosity or repetition of the tool name.

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?

This is a simple zero-parameter, read-only reference lookup with no output schema. The description tells the agent the data content (countries and ISO codes) and the practical scenarios where that data is used. Nothing essential for correct invocation is missing.

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 zero parameters and the schema confirms an empty properties object, so there is no parameter behavior to clarify. The description naturally cannot add parameter semantics, but per the rubric the baseline for zero params is 4.

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 and resource: 'List all countries with their ISO 2-letter codes.' This is clear and unambiguous. It does not explicitly name or contrast sibling tools like bunny_list_regions, but the country-specific scope is enough to differentiate it for most agents.

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 second sentence explicitly states the use case: reference data for geo-blocking, routing filters, and allowed/blocked country lists on pull zones. This gives clear context for when to invoke the tool, though it does not explicitly mention alternatives or say when not to use it.

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