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

readOnlyHint=true already establishes the safe-read profile, so the bar is lower. The description adds genuinely useful behavioral context by decoding status codes (50/100/200/750/1000) into business states and noting the underlying endpoint, which the annotations do not provide. It stops short of describing pagination defaults or response shape.

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 front-loaded clauses: purpose, filterable dimensions, then the status legend and endpoint. No filler, and the most useful detail (status semantics) is placed early. Slightly dense in the status run-on, but every element 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 11 optional params, 100% schema coverage and a readOnly annotation, the definition covers purpose, filtering, and status semantics adequately. The one gap is that no output schema exists and the description says nothing about the returned shape or paging envelope (limit/offset/count_all interaction), which the agent must infer.

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 in the schema is bare codes with only 'Only invoices with this status code', while the description maps each code to a real state (draft, open/due, partially paid, paid). That is meaningful semantic enrichment of a parameter.

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 ('List invoices') and enumerates the filter dimensions, so the agent immediately knows this is the collection-retrieval counterpart to sevdesk_get_invoice. It does not explicitly name a sibling, but 'List' vs 'get' is self-evident from the naming.

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 phrase 'filterable by status, number, date range and contact' implies when the tool is useful (bulk/queried retrieval) but gives no explicit when-to-use vs. when-not, and never routes the agent to alternatives like sevdesk_get_invoice for a single record or sevdesk_list_credit_notes for a different document type.

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