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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the description doesn't need to restate that this is a non-destructive processing operation. The description adds that it uses 'Boost Audio AI,' which hints at AI-based processing, but it doesn't disclose important behavioral traits such as what the output format is, whether processing is asynchronous, or any file size/format limitations. Thus, it adds only marginal transparency beyond the 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?

The description is two efficient sentences with no filler. It front-loads the core action ('Separate vocals from instrumental') and follows with a clear use case. Every word earns its place, making it an excellent example of 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?

While the schema and annotations provide some context (e.g., widget-based upload, safety profile), the description omits what the tool returns. With no output schema, the agent doesn't know if the result is a download link, two separate tracks, or a widget update. For a processing tool like this, that missing output specification leaves the description incomplete.

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 input schema has 100% coverage with detailed descriptions for all five parameters (audio_url, file_name, file_type, file_token, audio_base64), so the schema already explains parameter semantics. The description contributes no additional parameter-level insight, leaving the baseline at 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 clearly states the tool's function: 'Separate vocals from instrumental in MP3/WAV using Boost Audio AI.' It specifies the resource (vocals/instrumental) and format, and the use case ('isolate vocals or get an instrumental version') helps distinguish it from generic audio tools. However, it does not explicitly mention alternatives like boost_audio_stem_splitter for multi-stem separation, so it falls short of a perfect 5.

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 an explicit when-to-use instruction: 'Use this when the user wants to isolate vocals (acapella) or get an instrumental version of a song.' This is clear and actionable. But it lacks when-not-to-use guidance or alternatives, such as suggesting a stem splitter for more granular separation, so it doesn't reach the highest bar.

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