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

Annotations already cover readOnly/openWorld, so the description's additions matter: it discloses determinism ('no AI: the same input always gives the same answer') and a concrete payment requirement ($0.01 USDC on Base via x402). Those are real behavioral facts an agent needs, though error behavior and the set of aging categories are left unstated.

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 front-loaded, moving from purpose to inputs to output to behavior to price in a compact block. 'Deterministic rules, no AI' and 'the same input always gives the same answer' are slightly redundant but each still earns its place.

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?

There is no output schema, so the description correctly explains the return (aging category plus next action) and adds determinism and pricing context. It is essentially complete for a stateless read tool, missing only detail on the category taxonomy.

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?

With 0% schema description coverage, the description must carry the parameter burden and it does partially by naming all four inputs (invoice number, client reference, amount, days overdue). However it adds no format or unit guidance, leaving ambiguities such as the meaning of a negative daysOverdue (schema allows -365) unexplained.

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 a specific action (triage an overdue invoice), its inputs, and its outputs (aging category and next action), which clearly separates it from the base_* and audit_* siblings. It stops short of any explicit sibling differentiation, but the invoice-triage purpose is unambiguous.

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 framing question ('Which overdue invoice should be chased?') implies the use case, but there is no explicit when-to-use, when-not-to-use, or alternative named. Usage is only inferred from the rhetorical setup.

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