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

The readOnlyHint annotation already establishes that this is a safe read operation. The description adds the underlying GET /CommunicationWayKey endpoint and the dependency on sevdesk_add_communication_way, but it does not disclose auth requirements, rate limits, or response representation beyond the enumerated keys, so it adds only moderate context over annotations.

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 that are front-loaded with the purpose and the actual key values, followed by the usage dependency and endpoint. Every element is useful and there is no redundant or filler text.

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 tool with readOnlyHint and no output schema, the description provides everything an agent needs: what the tool returns, the exact key values, why it exists, and the underlying endpoint. No critical gap remains.

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?

The tool has zero input parameters, so the baseline is 4. The description does not need to explain parameter semantics, and its enumeration of possible key labels adds useful domain context about the output rather than input parameters.

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?

The description states a precise verb and resource: list the labels/keys a communication way can carry. It enumerates the actual key labels, making the resource concrete and distinguishable from sibling list_communication_ways, which lists actual communication ways rather than their 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?

It explicitly says the tool is 'Needed for sevdesk_add_communication_way', giving clear usage context. It does not, however, state when not to use it or point to an alternative such as sevdesk_list_communication_ways for retrieving existing communication ways.

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