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

Annotations declare destructiveHint=true, so a baseline exists, and the description adds the underlying endpoint (POST /CommunicationWay) plus the key_id default. It does not disclose what 'destructive' means here (e.g. whether setting main=true overwrites an existing main entry) or any auth requirements. Given annotations cover the safety flag, a 3 is appropriate.

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 compact sentences with zero waste; the core action is front-loaded and the endpoint/default notes follow. Every clause earns its place.

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 5-parameter mutation tool with 100% schema coverage and no output schema, the description supplies the endpoint, the key_id default guidance, and a pointer to the lookup tool. It is nearly complete, missing only clarification of the destructiveHint behavior.

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 schema already documents contact_id, type, value, main, and key_id in detail. The description only re-emphasizes the key_id default ('2 Arbeit/work'), adding marginal value beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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 (Attach) and resource (email address, phone/mobile number or website) bound to a contact. It is clearly distinguishable from siblings like sevdesk_list_communication_ways and sevdesk_list_communication_way_keys. An agent can identify the operation without opening the schema.

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 description gives concrete usage guidance on key_id ('2 Arbeit/work is a good default') and routes to sevdesk_list_communication_way_keys for valid values, which is useful context. However, it does not state explicit when/when-not conditions or alternatives for the whole operation.

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