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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, which cover safety and idempotency. The description adds value by explaining the data content and relationship to get_series_data, but does not describe pagination, format, or other behavioral details.

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 no wasted words. The first sentence states the core function, and the second provides actionable usage guidance. Perfectly front-loaded and concise.

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 no output schema and no parameters, the description is quite complete. It explains what the tool returns and how to use the results. A slight improvement would be to explicitly mention that the output is a list of code-name pairs, but the examples suffice.

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 schema coverage is 100%. The description adds examples of the data structure (e.g., 1 = World), which is useful beyond the schema. Baseline for 0 parameters is 4, and the description meets that bar.

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 geographic areas with M49 codes, using a specific verb and resource. It distinguishes from sibling list tools like list_goals and list_indicators by focusing on geographic areas.

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 explains the purpose and even suggests how to use the output (passing M49 code to get_series_data). However, it does not explicitly state when not to use this tool or mention alternatives, but the context is clear enough for a simple lookup tool.

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