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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds the return shape (id and name), which is useful, but says nothing about auth behavior or pagination beyond what the schema's email field carries.

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?

Tight and front-loaded: purpose first, then disambiguation, then return fields, then the endpoint. No filler, though the trailing 'GET /elements/voices' is marginally redundant with the tool name.

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 read-only list tool whose annotations carry the safety profile, an agent has everything it needs: what it lists, what it returns, and how it differs from the other voice lists. No output schema exists, and the description already names the returned fields.

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 optional parameter (email) with 100% schema description coverage, so the schema fully documents it. The description adds no parameter-level meaning, making the baseline 3 appropriate.

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 (list) plus resource (element voices) and even the returned fields (id and name). It explicitly distinguishes itself from the two nearest siblings, kling_list_voices and kling_list_tts_voices, and ties the list to kling_create_element voice.

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 names the alternatives it is NOT (kling_list_voices for Kling 4.0, kling_list_tts_voices) and pins its use case to character elements via kling_create_element, giving clear selection context. It stops short of an explicit 'use this when / don't use this when' rule, so it isn't a full 5.

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