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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds no behavior beyond that — nothing about the default page size, max limit, or result ordering — and merely repeats the status vocabulary already present in the schema.

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 tight sentence with the resource front-loaded and the filters trailing, with zero filler. It is slightly fragmentary — no verb such as 'list' or 'fetch' — but that costs little.

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?

For a simple read-only list tool with full schema coverage and rich annotations, the definition is adequate to call correctly. It stops short of explaining the return shape or the special 'filter' modes, which is the remaining gap an agent would hit at invocation time.

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%, so the baseline is 3. The description echoes the status and supplier filters but says nothing about the 'filter' parameter (needs_review, skonto) or the limit parameter, so it adds no meaning beyond the schema.

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 the resource precisely — incoming supplier invoices — and enumerates the optional filters, so an agent can tell this is a list/retrieval tool. It does not, however, distinguish itself from the sibling fetchOverdueIncomingInvoices, even though it lists 'overdue' as one of its own status values, leaving overlap ambiguity.

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?

'Optionally filtered by status ... or supplier' implies the call patterns but gives no explicit when-to-use or when-not-to-use guidance. In particular it never says whether to prefer fetchOverdueIncomingInvoices over this tool when looking for overdue items, which is the one routing decision an agent actually faces here.

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