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

No annotations exist, so the description carries the burden; it signals read-only reporting by describing a computed money total rather than an action, and it discloses the bucketing logic. It stops short of stating permissions, date/scoping behavior, or whether voided/paid invoices are excluded.

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?

One tight sentence, front-loaded with the object measured (money still owed) and immediately followed by the grouping semantics. No filler.

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 the return shape is covered, and the bucketing is spelled out. What's missing is any coverage of the required shop_id and any routing versus the very similar invoices_aging sibling.

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 (shop_id, uuid, required) is documented at 0% schema coverage, and the description never mentions it — no indication whether the shop is the caller's own, whether an empty result is possible, or how multi-shop accounts behave. With one undocumented param the description needed to compensate and does not.

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 names the resource (outstanding money on sent invoices) and the exact transformation (grouped into 0-30 / 31-60 / 61-90 / 90+ day buckets), so an agent knows precisely what this returns. It does not, however, distinguish itself from the sibling invoices_aging, which appears to cover overlapping ground.

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 statement of when to call this versus invoices_aging, reports_revenue, reports_week, or reports_today. The agent must infer from the name alone that this is the receivables-aging report, and no exclusions or prerequisites are given.

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