list_countries

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

No annotations are provided, so the description carries the burden. It discloses that the tool returns a list of countries with ids and operators, and hints at usage in order_number. However, it doesn't mention the optional search filter or whether the list is fully returned, paginated, or any side effects. The description is adequate but not rich.

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 short sentences with no fluff. It front-loads the core purpose and includes a practical usage hint without wasted words.

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 list tool with one optional parameter and no output schema. The description explains the return contents (country id, operators) and how to use the id, which covers the essential information. It doesn't detail the response format (e.g., array structure), but given the low complexity, it's sufficiently complete.

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 description covers the only parameter (search) 100%, so the description need not add parameter details. The description doesn't mention the search filter, but since the schema fully documents it, the baseline of 3 is appropriate. No additional meaning is added beyond the schema.

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 explicitly states the tool lists countries that numbers can come from, and includes id and operators. It also clarifies the purpose of the id in the order_number workflow, distinguishing it from sibling tools like list_services.

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 gives clear context: this is the tool for getting country information to use in order_number. It doesn't explicitly state when not to use it, but the integration hint implies when it's needed. Sibling alternatives are not mentioned, but no other sibling covers countries.

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