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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered without the description. The description adds the underlying endpoint (GET /Contact/{contactId}), which helps an agent familiar with the sevdesk API, but says nothing about error behavior for unknown ids or the shape of the returned contact.

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?

Two short sentences, front-loaded with the action and scope, and the endpoint reference is compact. Nothing is padded or redundant.

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 single-record lookup with a fully documented two-parameter schema and a readOnly annotation, the description plus structured fields are sufficient to invoke correctly. The only gap is that, with no output schema, the description does not hint at what the returned contact contains.

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 both contact_id and embed fully documented in the schema, so the baseline is 3. The description adds no syntax, format, or expansion semantics for embed beyond what the schema already states.

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 ('Fetch') and resource ('a single contact by id'), which lets an agent distinguish it from sevdesk_list_contacts and sevdesk_create_contact. It does not name those siblings explicitly, so differentiation is implied rather than spelled out.

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?

'By id' implies the precondition that the caller already has a contact id, which is useful routing signal versus the list tool. However, there is no explicit when-to-use guidance, no mention of what to do without an id, and no named alternative.

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