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

Annotations already cover read-only, idempotent, non-destructive, and closed-world behavior. The description adds useful context that results are matched to invoices and include journal entries, and hints at Enterprise plan availability, but it does not disclose whether the report must exist, whether it is generated on demand, or what happens if the month is not finished.

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 compact and front-loads the deliverable. The trailing fragment 'Work and coding agents Enterprise.' is abrupt but still conveys plan availability; it could be integrated more cleanly.

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?

An output schema exists, so return structure need not be explained. However, for a report-generation tool with a single required parameter at 0% schema coverage, the definition should clarify month semantics and when to prefer this over adjacent reporting tools such as month_end or reconciliation_status.

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 single parameter has 0% schema description coverage, so the description must compensate. It adds the meaningful constraint that the month should be 'finished,' while the YYYY-MM format is only conveyed by the schema pattern; the description does not explain timezone, month boundary, or what happens for incomplete months.

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 identifies a specific resource (a finished month's chargeback breakdown by cost center, team, person, tool, matched to invoices with journal entries), but it reads as a noun phrase rather than a clear action and does not explicitly distinguish itself from siblings like month_end, get_spend, or reconciliation_status.

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?

There is no explicit guidance on when to call this tool versus alternatives such as month_end, get_spend, or reconciliation_status. The phrase 'finished month's' weakly implies it is for closed periods, but no preconditions or exclusions are stated.

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