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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds valuable context beyond annotations: 'public' implies no auth, and it discloses filtering/pagination behavior and the return content (ranked users, display names, weekly totals). It does not mention rate limits or potential network behavior, but the annotation coverage plus description is strong.

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 a single, tightly packed sentence with no filler. It front-loads the main purpose and conveys all essential information: resource, filters, pagination, and return type. Every phrase earns its place.

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 simple read-only leaderboard-fetching tool with an output schema, the description is fully sufficient. It covers the purpose, all parameters (filtering and pagination), and summarizes the return data. The annotations and output schema handle safety and response details, so no critical gaps remain.

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 0%, but the description explicitly names 'language', 'country_code', and 'paginate' (which maps to the 'page' parameter), giving high-level semantics for all three parameters. It does not provide formats or allowed values, but it compensates well for the schema's lack of descriptions.

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 action ('Fetch'), the specific resource ('WakaTime's public coding leaderboard'), and includes the scope ('public') and what it returns. This distinguishes it from sibling tools, none of which appear to be leaderboard-related. The verb+resource combination is unambiguous.

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 provides clear context for use: it is a public leaderboard, and it explains optional filtering and pagination. However, it does not explicitly state when to use this tool versus alternatives or include any exclusions (e.g., 'use X instead for private data'). Given the sibling list has no directly competing leaderboard tool, this is acceptable.

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