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

Annotations already declare read-only/safe (readOnlyHint=true, destructiveHint=false), so the safety profile is covered. The description adds real behavioral context beyond that: pagination (up to 100 per page, pass next_cursor back as cursor), ordering (newest first), and the auth requirement (Cotlet API key with access to this app). Rate limits and error behavior are not mentioned, so not 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?

It is front-loaded with the purpose, but the opening two sentences are largely redundant – 'Invoices with number, customer, status, dates and total, newest first' repeats what the next sentence re-states in full ('Lists invoices newest first, with the customer, status, invoice date, due date and gross total'). Roughly a sentence of duplication that does not earn 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 carries the return-value burden, and it does: it enumerates the returned fields, ordering, and pagination. Combined with annotations covering safety and the description covering filtering, auth, and paging, an agent has everything needed to call this correctly.

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, but the description adds meaning the schema lacks: the status enum values map to real UI tabs with localized names, and it explains the cursor round-trip ('pass next_cursor back as cursor'). It also frames the filter intent for customer/number/date range, going beyond the raw field descriptions.

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 (lists) and resource (sevdesk invoices), plus the exact fields returned (number, customer, status, invoice date, due date, gross total) and sort order (newest first). An agent can distinguish this from siblings like sevdesk_get_invoice or sevdesk_create_invoice_draft without opening any schema.

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?

It gives clear operating context: filter by customer, invoice number, or date range, and the status values map to the Rechnungen tabs (due = Fällig, cancelled = Storno). It never explicitly names when to prefer this over sevdesk_get_invoice or sevdesk_list_vouchers, so it stops short of full when/when-not guidance.

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