compare_data

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

With no annotations, the description carries the full burden. It discloses a key limitation ('only supports comparison for 1 year') and clarifies that multi-year comparisons require a different tool. However, it does not describe the return format or behavior in edge cases (e.g., invalid region names), which would improve transparency.

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 concise and front-loaded. It opens with a clear one-sentence purpose, then provides usage guidance, a critical constraint, and relevant examples. Every sentence adds value with no redundancy.

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 tool with moderate complexity (3 parameters, no output schema), the description provides strong contextual coverage: purpose, usage, constraints, and examples. However, it does not describe the response format or error behavior, which is a minor gap given the lack of an output schema.

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 provides 100% coverage of the three parameters, including examples for each. The description does not add further semantic detail beyond the schema, so 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 uses a clear verb 'Compare' and resource 'statistical data across regions', and explicitly distinguishes from siblings by noting it handles single-year comparisons only. The provided examples further clarify the tool's purpose and scope.

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 explicitly states when to use the tool ('when the user wants to compare data between 2 or more regions') and provides an explicit alternative for multi-year comparison ('use get_trend per region'). This is clear, actionable guidance.

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