get_usage_stats

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

No annotations are provided, so the description carries the full burden. It explains parameter defaults and return format, but does not disclose potential side effects, error handling, or rate limits. The description is adequate but not extra insightful.

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 uses a structured docstring format with an Args list, making it easy to parse. It is relatively concise, with the purpose stated first. However, some redundancy exists (e.g., repeating defaults in both description and schema).

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 5 parameters, no required parameters, and an output schema, the description covers parameters adequately and states the return type (JSON). It lacks details on error cases or rate limits, but for a read-only stats tool, it is 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?

Schema description coverage is 0%, but the description explains each of the 5 parameters: start_unix, end_unix, metric, breakdown_type, and aggregation_interval, with defaults and examples. This adds significant meaning beyond the raw schema, though it could explicitly list allowed enum values for metric and breakdown_type.

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 'Get character/credit usage statistics over a time window,' specifying the verb 'Get' and the resource 'usage statistics'. It distinguishes from sibling tools which are focused on audio, voice, dubbing, etc., making the purpose 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 implicitly indicates this tool is for retrieving usage statistics, and sibling tools are all about other domains, so context is clear. However, it lacks explicit guidance on when to use or not use this tool, or mention of prerequisites.

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