ncloud_globalcdn_get_usage

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

The annotation readOnlyHint=true already conveys the read-only nature. The description adds context about the data type (transfer/traffic volume) and the parameter scope (multiple instances, time range), which is useful but minimal. It does not disclose return format, pagination, or any potential side effects beyond what the annotation covers, so it does not significantly exceed the annotation-provided 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 a single, well-structured sentence that front-loads the action and resource, then adds the key qualifiers (instances and time range). Every word earns its place, with no redundant or unrelated information.

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 tool with well-documented parameters and a readOnlyHint annotation, the description sufficiently communicates the tool's purpose and scope. While there is no output schema and the description does not describe the return format, the data type is implied by the description, making it complete enough for an agent to invoke correctly. A minor gap is the lack of detail on response structure, but the simplicity of the operation mitigates this.

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 input schema has 100% parameter description coverage, with clear descriptions for startDate, endDate, and cdnInstanceNoList. The description adds no additional parameter detail beyond the schema, so the baseline of 3 applies, indicating the schema handles parameter semantics adequately.

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 ('Get'), the resource ('Global CDN usage data'), and the scope ('for one or more instances over a time range'). The parenthetical '(transfer/traffic volume)' distinguishes it from sibling tools like monitoring or list instances, making it unambiguous which tool to select.

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 on what the tool does, allowing an agent to infer when to use it (when usage data over a time range is needed). However, it does not explicitly mention alternatives or exclusion cases, such as 'use get_monitoring instead for performance metrics', so it falls short of providing explicit when-to-use vs. when-not-to-use guidance.

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