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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description earns credit by adding non-obvious behavior the annotations cannot convey: the range is inclusive, a bare end date resolves to end-of-day, and it maps to the SOAP GetInvoicesByDateRange call. It omits result ordering and total-count behavior, which keeps it from a 5.

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?

Three short clauses with no filler; the scope, date semantics, and paging note are all front-loaded in the first sentence. Every element carries information an agent would otherwise have to guess.

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, the description carries the burden of saying what comes back, and 'Sales invoices ... paged here' leaves the record shape and whether paging metadata is returned unstated. It also gives no guidance for distinguishing this from the other invoice-list siblings, though the read-only annotations cover the safety dimension.

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 coverage is 100%, so the baseline is 3. The description still adds real meaning beyond the schema: it clarifies that both bounds are inclusive and that a date-only end_date includes the whole day, semantics the schema's 'Last invoice date' wording does not supply. Limit/offset behavior is only hinted at with 'paged here'.

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?

States a specific verb and resource ('Sales invoices dated within a range ... paged here'), which distinguishes it from date-unrelated siblings like list_overdue_invoices or list_unpaid_invoices. It never names the date-scoped alternatives (kashflow_list_recent_invoices, kashflow_list_customer_invoices) explicitly, so the differentiation is implied rather than spelled out.

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 date-range framing implies when to reach for this tool, and 'paged here' signals the pagination path, but there is no explicit statement of when to prefer it over kashflow_list_recent_invoices or kashflow_list_customer_invoices, and no exclusions. Usage is inferable, not guided.

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