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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the endpoint mapping and the shape of returned items, which is some useful context, but it says nothing about paging defaults, total counts, or whether the list is empty for invoices without positions.

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?

One tight sentence plus the REST endpoint reference, front-loaded with the core purpose and the returned fields. The endpoint mapping is arguably redundant for invocation but is cheap and useful for traceability.

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 describing returns and does so by naming the item fields (name, quantity, price, tax rate, sums). For a simple read-only list endpoint this is nearly complete, with only paging/empty-result behavior left unstated.

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 100%, with embed, limit, offset and invoice_id all documented in the schema itself. The description adds no meaning beyond the schema (e.g., no note on how offset/limit interact for positions), so the baseline 3 applies.

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 ('List') and resource ('positions (line items) of one invoice') and even enumerates the returned fields, so the agent knows exactly what comes back. It does not explicitly contrast with the sibling sevdesk_get_invoice, but the 'of one invoice' scoping makes the distinction fairly obvious.

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 'of one invoice' implies you must already have an invoice id, but there is no explicit when-to-use guidance, no mention of when to prefer this over sevdesk_get_invoice, and no note about paging origins or prerequisites. Usage is only weakly implied.

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