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

The annotations already declare readOnlyHint=true, and the description complements this by explaining the report's structure (grouped by supplier, with aging/overdue information). No contradiction exists, and the description adds behavioral context about what the report presents beyond the safety hints.

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 a single, memorable sentence with an effective em-dash structure. It is front-loaded with a relatable question and wastes no words.

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?

The tool is simple: one optional parameter, no output schema, and safety annotations provided. The description explains what the report contains (payables aging by supplier). The only gap is the lack of clarification around the 'asOf' parameter, but for a simple report this is a minor omission.

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 description does not mention the only parameter 'asOf' at all. Since schema description coverage is 0%, the description fails to compensate for the lack of parameter explanation. The parameter name and pattern are somewhat self-explanatory, but the description adds no semantic value for how the date affects the aging report.

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 specifies the exact resource ('accounts-payable aging by supplier') and the informational content ('whom you owe money and how overdue it is'). It clearly distinguishes itself from the sibling tool 'ar_aging' by explicitly naming the accounts payable side.

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 provides clear context for when to use the tool: when you need to understand outstanding payables and their overdue status. It does not explicitly name alternatives, but the 'accounts-payable' phrasing versus the sibling 'ar_aging' implies the differentiation, and no exclusions are needed.

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