get_usage

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

No annotations are provided, so the description bears the full burden of disclosing behavior. It indicates that the tool is a read-only status check (characters used vs quota), but it does not specify details such as whether the data is current, cached, or if any external calls are made. It adds minimal context beyond the obvious.

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, concise sentence that is front-loaded with the key information ('Characters used vs quota'). It uses no filler words and every word contributes to the meaning.

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 that the tool has no parameters and an output schema exists, the description is largely complete. However, it could provide more context about what specific quotas or usage metrics are included (e.g., daily vs total, whether it's the current key), but these details are likely captured in the 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 tool has zero parameters, so the description has no need to explain parameter semantics. The baseline for tools with no parameters is 4, and the description does not introduce any param-related confusion.

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 reports 'Characters used vs quota' for the configured API key, which is a specific and distinct purpose compared to sibling tools (synthesize, list_voices, list_languages). It uses a clear verb ('used') and resource ('characters' and 'quota') to convey its function.

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 implies that this tool should be used to check API key usage and quota status, but it does not explicitly state when to use it or contrast it with alternatives. There is no mention of prerequisites or when not to use it, so the guidance is only implied.

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