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

With no annotations, the description carries the full behavioral burden. It usefully discloses the return shape (reminder 1/2/final notice with due dates) and a quota (free tier: 3 concurrent invoices), but says nothing about permissions, idempotency, or what happens when a duplicate invoice is already on the register.

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, front-loaded with the action and outcome, then the tier constraint. Slightly wasteful in re-listing the required parameters that the schema already names, but no fluff overall.

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 10-parameter mutation tool with no annotations and no output schema, the description compensates well by explaining what is returned (the escalation ladder and its dates). Gaps remain around duplicate handling and permissions, but the core call-and-result picture is complete.

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 90%, so the schema already documents fields like amount_minor, currency, due and gaps. The description only restates 'amount in integer cents' and the field list, adding no meaning beyond the schema; baseline 3 applies.

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 states a specific verb (register) and resource (an unpaid invoice) and specifies the concrete payoff: a three-step escalation schedule with dates. It is clearly distinguishable from read-only siblings like invoice_status or overdue_list, but it never names an alternative tool, so it stops short of full sibling differentiation.

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?

'Start chasing an unpaid invoice' implies the trigger condition, and the free-tier limit (3 concurrent unpaid invoices) is a real usage constraint. However, there is no guidance on alternatives (e.g. invoice_status, chase_today) or on prerequisites such as what to do when the invoice is already registered.

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