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

Annotations already declare it is a read-only, non-destructive, closed-world operation, so safety is covered. The description adds the bucketing behavior, which is useful. However, it does not state whether the result is as-of-now or how it handles multiple currencies, nor any auth scope. With annotations carrying the safety profile, a 3 is appropriate.

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 for the definition, one for usage. Front-loaded with the core concept and zero waste.

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?

Complete enough for a zero-parameter read-only summary. The description tells the agent what the output means (aging buckets) and when to use it. It lacks edge-case notes (e.g., currency, as-of date), but no output schema exists, so the description carries the return-value burden and does so adequately.

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 are zero parameters, so there is nothing to document. The description correctly adds meaning by defining the bucket boundaries, which would otherwise be unknown. Baseline 4 for zero params.

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 the specific resource (accounts-receivable aging) and the exact output structure (buckets: current, 1-30, 31-60, 61-90, 90+). Distinguishes itself from sibling ar_aging and from related tools like overdue_tasks and find_invoices by defining the specific aggregation.

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?

Provides a clear usage example ('how much are we owed by buckets') that indicates when to invoke. Does not explicitly name alternatives or exclusions, but the example is enough for an agent to select it over find_invoices or overdue_tasks.

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