get_usage_statistics

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

With no annotations, the description carries the full burden, and it does disclose meaningful behavior: the aggregation scope ('Calculate usage summary across all projects') and the conditional nature of the breakdown ('when available'). It does not state permission or admin-scope requirements, which for a billing/usage endpoint is a real omission, nor does it note that no project filter is accepted.

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?

Purpose is front-loaded in the first sentence and the 'Use when' block is a clean routing aid. The middle 'Functions:' bullet list partially restates the opening line and the metrics list, so a little content is redundant, but nothing is confusing or bloated.

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 two-optional-param read tool with an output schema, the description covers purpose, returned metrics, and triggers. The notable gap is that the agent is not told the call aggregates across all projects with no per-project filtering — a caller looking to scope to one project would have to infer that from the absence of a parameter.

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 coverage is 100% and both parameters document their format and defaults, so the schema carries the semantics. The description only alludes to 'a specified time period' without restating or extending the date semantics, which is acceptable at baseline but adds nothing.

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?

States a specific verb and resource ('Get usage statistics for projects') and grounds it in a known CLI equivalent, so the operation is unambiguous. It differentiates adequately from quota/project-detail siblings by naming the metrics returned (RAM MB-Hours, CPU Hours, Disk GB-Hours), though it never names an alternative tool directly.

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 'Use when user requests usage statistics, billing information, resource consumption analysis, or project usage reports' line gives concrete invocation triggers that map well to real user phrasing. It stops short of exclusions — it never says to prefer get_quota or get_resource_monitoring when the user actually wants limits or live metrics, which is the main ambiguity against these siblings.

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