who_owes_me_money

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds behavioral detail about the computation: it aggregates open invoice balances and ranks customers by amount due. This goes beyond the annotations, but it does not cover finer details like pagination or date ranges; the presence of an output schema mitigates 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?

Two sentences, zero filler. The first sentence provides natural-language entry points, and the second explains the action. No redundancy.

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?

For a simple read-only aggregator with one optional parameter and an output schema, the description covers the essential purpose. It could mention that top_n controls the list length or clarify 'open' means unpaid, but overall it is sufficient for a competent agent.

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 input schema has one parameter, top_n (integer, default 10), with no description (0% schema coverage). The description does not mention the parameter or explain how it controls results, though it implies a 'top customers' limit. Since the description fails to compensate for the schema's lack of documentation, this dimension is weak.

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 explicitly answers three natural-language queries and states the core action: 'Totals open invoice balances and lists top customers by amount due.' This clearly differentiates it from siblings like search_invoices (which would search individual invoices) and get_financial_summary (broader financial view).

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 implies usage via the questions it answers ('Who owes me money?'), but it does not explicitly state when to use this tool over alternatives like search_invoices or get_financial_summary. There is no mention of exclusions or alternative tools, so it relies on inference.

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