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

Annotations only declare readOnlyHint=false, openWorldHint=true, and destructiveHint=false. The description adds meaningful behavior beyond these: the tool does not directly return the conversion result but a 'private upload instruction,' and it instructs that only the source vocal should be uploaded. This conveys an upload-then-poll workflow that annotations alone would not reveal. No contradiction with 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?

Three short sentences with the usage context front-loaded before the workflow steps. Every sentence earns its place; no filler. Slightly more could be trimmed, but it is appropriately tight.

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?

An output schema is present, so return values need not be explained in the description. The description covers the essential workflow (private upload instruction, upload source vocal, then call get_voice_conversion with same ID), which is sufficient for an agent to proceed correctly. Minor gap: it does not mention the upload size limit or byte verification that sizeBytes enables, but the schema covers that.

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 all 5 parameters with definitions (modelId, fileName, sizeBytes, transpose, durationSeconds). The description adds no additional parameter meaning beyond what the schema provides, so the baseline 3 applies.

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 (create), resource (voice conversion), and scope (private voice model, one vocal recording). The description also differentiates from get_voice_conversion by framing it as the follow-up call, which helps an agent distinguish the creation step from the retrieval step.

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 frames the trigger condition ('when the user has selected a private voice model and wants to convert one vocal recording') and lays out the required follow-up sequence (upload source vocal, then call get_voice_conversion). It does not name explicit exclusions or alternative tools, but the stated context is clear enough to route an agent.

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