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

Annotations only assert readOnlyHint=true, so the safety profile is covered; the description adds genuine behavioral context beyond that: the non-obvious default that only organisations are returned and that include_persons maps to sevdesk depth=1. It also anchors the tool to the underlying endpoint (GET /Contact). It stops short of noting pagination behavior or result size.

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 compact sentences, front-loaded with purpose and then the default-vs-opt-in behavior, which is the most useful callout. Every sentence carries information; the API endpoint note is marginal but harmless.

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 read-only list tool with no output schema and fully documented parameters, the description covers the one genuinely surprising behavior (orgs only by default). It could mention paging given limit/offset exist, but nothing critical to correct invocation is missing.

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 all 11 parameters are already documented, including include_persons and the category_id enum values. The description's only parameter-relevant statement (include_persons and the organisation-only default) restates what the schema already says, so it adds little beyond the baseline.

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 clear verb+resource ('List contacts') and enumerates the entity subtypes it covers (customers, suppliers, partners, prospects), so an agent knows the dataset. It does not explicitly distinguish itself from the singular sevdesk_get_contact sibling, but the plural/list framing makes the split inferable.

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?

Explains the default return semantics ('only organisations') and the flag to broaden it ('set include_persons'), which implies when the parameter matters. However, it gives no explicit when-to-use vs sevdesk_get_contact or sevdesk_create_contact, and no conditions under which this tool should not be used.

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