Customer payment history

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds the useful note that the result includes a lateness pattern, not just raw invoices, but says nothing about the time window behind 'usually' or how far back 'recent' reaches — both of which materially change interpretation of the output.

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, no filler, and the usage cue follows immediately after the purpose statement. Every clause 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?

With no output schema and zero schema coverage, the description should say more about the shape of the returned history and the meaning of its two parameters. It conveys intent well enough to call the tool, but not enough to interpret 'how late they usually pay' reliably.

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 carries the full burden. It never mentions customer_id at all and never explains that 'recent' is controlled by a limit parameter defaulting to 12 with a 100 cap — an agent cannot infer the result-window semantics from the description alone.

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 the resource and its contents clearly ('a customer's recent invoices and how late they usually pay'), which tells an agent this is a per-customer payment-behavior lookup. It does not name the retrieval verb or explicitly distinguish itself from list_overdue_invoices or receivables_summary, so differentiation is left partly implicit.

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 it before deciding whether a reminder is worth sending' gives a concrete decision context that links directly to the send_invoice_reminder sibling. What's missing is any exclusion — it never says when a different sibling (e.g. receivables_summary) is the better choice.

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