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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds two useful behavioral facts beyond them: results are sorted oldest first and each row carries amount and supplier. That is real added context, though pagination, date basis and currency handling remain undisclosed.

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?

A single sentence that front-loads the entity and filter, then appends ordering and returned fields. Every clause carries information; nothing is repeated from the title or annotations.

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 no parameters, the description carries the burden of describing the result set, and it does so at a high level (overdue, open, oldest first, amount and supplier). For a simple read-only tool this is close to sufficient, with only minor gaps around result shape and volume.

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 tool takes zero parameters, so there is nothing to disambiguate and the baseline is 4. The description correctly introduces no invented parameter concepts such as date ranges or filters.

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 resource (supplier/incoming invoices) and a precise filter (still open and past due date), which separates it from the broader fetchIncomingInvoicesContext sibling without naming it. It is a noun phrase rather than an explicit verb, but the retrieval intent 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?

Usage is implied by the filter definition: an agent can infer this is the tool for overdue payables. However, no explicit when-to-use versus when-not-to-use guidance is given, and no alternative tool (e.g. fetchIncomingInvoicesContext or fetchDunningQueue) is named for cases where the agent wants all open invoices or reminders.

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