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

Beyond the readOnly/idempotent annotations, the description discloses plan gating per format, on-demand generation latency (up to a minute for MIDI/MusicXML), differing link lifetimes (mp3 playUrl about an hour, wav signed link valid 24h with 'expires'), and that MIDI/MusicXML links must be fetched with the API token. These are exactly the operational facts an agent needs before calling.

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?

It is a single densely packed paragraph, but it is front-loaded with the resource and then organizes details by format, and every clause (plan limits, latency, expiry, auth) carries information. A slightly more scannable structure would help, but there is little filler.

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?

There is no output schema, yet the description explains the return shape ({ url }, playUrl plus playUrlExpires, or a signed link with expires) and the auth requirement for file formats. Combined with the fully-documented input schema, an agent has everything needed to call and consume the result.

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%, so the schema already documents songId and the format enum; the description goes further by tying each format value to a distinct return behavior and plan requirement. That adds genuine meaning beyond the enum labels.

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 resource (a finished song's file) and enumerates the four formats it can return, so an agent can tell this is the file-retrieval tool rather than a metadata tool like acemusic_get_song. It stops short of explicitly contrasting itself with the sibling that returns song metadata.

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?

Usage is only implied: the tool needs a finished song and the description notes which formats require a paid plan, which is useful selection context. There is no explicit when-to-use/when-not statement or named alternative for the metadata case (acemusic_get_song), leaving the choice to inference.

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