msio_ar_aging

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

Annotations already mark read-only/idempotent/non-destructive, and the description adds non-obvious behavioral facts: the invoice endpoint has no server-side filters, large accounts are capped at max_invoices, and metadata.coverage_pct must be checked. This goes beyond what any annotation or schema field conveys.

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?

Each section (purpose, use-when, not-use-when, gotchas) is separate and front-loaded with the most important operation. No sentence is redundant; the content is dense but organized.

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?

Given an output schema exists, return-value documentation is not required here. The description covers selection criteria, the alternative tool, and the critical data-completeness limitation (cap and coverage percentage), giving an agent enough context to choose and invoke the tool safely.

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?

Schema description coverage is 0%, so the description needed to clarify the five parameters. It only elaborates max_invoices (cap) and indirectly payment_terms_days via 'overdue'; customer_id, include_zero_amount, and minimum_amount_cents are left entirely to their schema titles and defaults.

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 opens with a specific verb and resource: 'Bucket overdue invoices by age for accounts receivable analysis.' This clearly identifies what the tool does and its domain, and the DO NOT USE clause differentiates it from hcp_list_invoices, so an agent can distinguish it from siblings.

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?

'USE WHEN' enumerates concrete scenarios and question phrasing ('How much money is owed?', AR review, collection priority, cash flow). 'DO NOT USE WHEN' explicitly routes to hcp_list_invoices for specific invoice lookup, giving both positive and negative selection criteria.

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