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

The description adds behavior beyond the readOnlyHint annotation by stating that the tool downloads the media from a URL, produces a modulated copy, and returns the resulting file. It also discloses the per-call cost of 10 points. With annotations already covering safety, this is useful but does not specify the exact output format or delivery mechanism.

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 compact and front-loaded with the core purpose, followed by format support, return behavior, and cost. The English and Korean sentences are redundant for token efficiency, but the bilingual repetition is justified for the target audience. No irrelevant details are included.

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 two-parameter synchronous tool with full schema coverage and readOnlyHint, the description covers selection and invocation basics, including supported formats and return behavior. However, with no output schema, it leaves the output contract vague by only saying 'returns a modulated file' without specifying whether the result is a URL, binary data, or some other representation.

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 type (1: low, 2: high) and media_url (allowed formats, max size). The description only adds natural-language examples that overlap with the schema, such as MP3/WAV and MP4/MOV, without contributing new parameter semantics.

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 specific verb ('modulate') applied to a clear resource ('the voice in a video or audio file') with a concrete outcome ('lower or higher pitch'). This unambiguously separates it from media-related siblings like video_to_mp3, stt, and tts_jobs_create, even though no sibling is named.

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 gives clear context for when to use the tool: whenever a user needs pitch modulation on a video or audio file. It also lists supported formats (MP3, WAV, MP4, MOV), which helps an agent decide input suitability. It does not explicitly mention alternatives or exclusions, so it stops short of a perfect score.

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