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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered. The description adds that output spans credits, emails processed, per-endpoint/source counts, a daily breakdown, and recent activity, but says nothing about auth requirements, retention, or rate limits beyond that.

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?

A single well-structured sentence front-loads the purpose and then enumerates the returned metrics. Every clause earns its place by describing contents; there is no filler or repetition.

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 usefully enumerates what the response contains, and both parameters are fully specified in the schema. The main remaining gap is the absence of guidance on how this relates to the credit/account siblings, which is minor for a read-only reporting tool.

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 100% and both parameters are documented in the schema, including the limit bounds and default and the period enum/default. The description only restates the period options ('day, week, or month') without adding format or interpretation detail, so baseline 3 is warranted.

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 clear verb ('Return'), resource ('usage statistics'), and scope ('for the account over a period'), and enumerates the reported metrics. It does not explicitly distinguish itself from the closest sibling get_credits, which likely reports a balance rather than a breakdown, so sibling differentiation is only implied.

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 names the supported periods (day/week/month) but gives no guidance on when to choose this tool over get_credits, get_account, or get_job_results. There is no when-to-use context and no exclusions, so the agent must infer the choice.

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