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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds that this is a static enum taxonomy by listing every value and the underlying endpoint (GET /CommunicationWayKey), which means an agent knows the result is complete and cacheable. It stops short of explicitly saying the list is static/param-free, keeping it from a 5.

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 tight fragments: purpose + values, the dependency, and the endpoint. Zero waste, front-loaded, and the long value list is justified because it is the tool's entire payload.

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 zero-parameter lookup with no output schema, the description fully compensates by enumerating the complete key set, so an agent can even skip the call in some cases. Nothing required to invoke or interpret it correctly 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?

Zero parameters, so the baseline of 4 applies. There is nothing for the description to clarify beyond confirming the tool takes no input, which the empty schema already communicates.

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?

Specific verb+resource ('list the labels a communication way can carry') and immediately enumerates the exact values returned (1 Privat, 2 Arbeit, 3 Fax, 4 Mobil, 6 Autobox, 7 Newsletter, 8 Rechnungsadresse). The enumeration effectively distinguishes it from the similarly named sibling sevdesk_list_communication_ways, which returns actual way records rather than this key taxonomy.

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?

Explicitly states the consumption context: 'Needed for sevdesk_add_communication_way,' naming the exact sibling tool that depends on these keys. An agent knows precisely when to call this (as a prerequisite lookup before adding a communication way) rather than guessing.

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