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

readOnlyHint=true is already declared, so the safety profile is covered. The description adds real behavioral context beyond that: the resolved entity can be a customer and/or vendor, the response includes contact persons and addresses, and it returns lexwareAppUrl. It does not, however, mention the endpoint's error case (unknown id) or pagination/embed options.

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 front-loaded sentence that leads with the verb and resource, then the returned fields, then the URL convenience and the underlying endpoint. No filler.

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 usefully previews the response shape and flags lexwareAppUrl. For a single-id read this is largely complete, though the 'customer and/or vendor' ambiguity and missing error behavior leave minor gaps.

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?

Only one parameter, and the schema documents it at 100% coverage including the UUID pattern and its origin. The description repeats 'by id' but adds no syntax or format detail beyond the schema, 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 and resource ('Get one contact') scoped by id, and enumerates the returned data (customer/vendor numbers, contact persons, addresses, emails, phones, note). This clearly separates it from the sibling lexware_list_contacts, which returns many.

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?

Usage is implied by the required id, and the schema description points to lexware_list_vouchers / lexware_list_contacts as the source of that id. There is no explicit when-to-use or when-not-to-use statement relative to the list siblings.

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