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

Annotations already indicate destructiveHint=true and readOnlyHint=false, so the mutation aspect is clear. The description adds value by noting that the tool 'Consumes Wubble requests or credits', which is important cost-related behavior not captured in annotations. This additional context justifies a score above baseline.

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?

The description is very concise with two short sentences, no filler. However, it is perhaps too brief given the tool's complexity and sibling set; it could be slightly expanded to improve clarity without losing conciseness.

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?

Despite having an output schema and multiple parameters, the description does not explain what the tool returns or provide operational context. It leaves the agent without full understanding of the tool's end-to-end behavior, making it insufficiently complete.

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 coverage is 100% with all parameters described. The description does not add any new meaning or clarify parameter usage beyond what the schema already provides, so the score remains at the baseline of 3.

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 'Change Wubble voice' which is a verb+resource pair, but the meaning is vague: it doesn't clarify whether it changes the voice of an existing audio or converts audio to a target voice. The schema implies conversion from source_url to target_voice_id, but the description lacks this detail, making it less specific than it could be.

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 provides no guidance on when to use this tool versus alternatives like wubble_text_to_speech or wubble_dub_audio. It only mentions credit consumption but no context about prerequisites, exclusion criteria, or comparative scenarios.

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