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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, covering the safety profile. The description adds one genuine piece of non-obvious context: results are scoped to data visible to the linked Market Brew account. It says nothing about aggregation windows, pagination, or freshness, so it adds value but not richly.

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?

Two short sentences, so raw length is fine, but the first sentence is pure restatement of the name and earns no place. Front-loading is acceptable; only the account-scoping clause carries 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?

With no output schema, the description should at least hint at the shape or granularity of returned metrics, and it does not. The nested query object also goes unexplained in the description. For a metrics-aggregation tool surrounded by similar siblings, this leaves the agent under-informed.

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?

There is a single optional 'query' parameter and the schema documents it at 100% coverage, including the full list of accepted filters (customerId, crewIds, websiteId, serverHost, startDate, endDate). The description contributes nothing beyond the schema, so the baseline 3 applies.

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 merely restates the tool name and title ('get aggregate system usage metrics') with no added specificity about what is aggregated or over what dimensions. It does not distinguish this tool from close siblings such as get_usage_report, get_usage_metric_history, or get_usage_report_history, which an agent would need to tell apart.

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?

'Use this when the user asks to get aggregate system usage metrics' is a circular condition — it names no distinguishing user intent, no prerequisite, and no alternative tool. With several usage/report/metrics siblings present, the absence of any routing guidance leaves selection ambiguous.

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