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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds a genuinely useful, non-structured fact — 'Costs 1 credit' — which lets an agent budget calls. It stops short of noting failure modes for invalid or private sound IDs.

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?

Two short sentences, front-loaded with the resource and then the payoff fields. The opening 'Sound / song details.' largely restates the title, which is the only wasted fragment.

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?

With no output schema, enumerating the returned fields is the right move and is done well. However, the undocumented cache_max_age parameter and the absence of any guidance on the songVideos companion leave gaps for a 2-parameter lookup tool.

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 50%: 'song' is documented as a music id or tiktok.com/music URL, but 'cache_max_age' has no description anywhere. The description mentions no parameters at all, so it does not compensate for the undocumented half.

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 names the resource (a TikTok sound) and enumerates exactly what is returned: title, artist, album, cover, clip length, and video usage count. That distinguishes it in practice from tiktok_songVideos, which lists the videos themselves, though the sibling is never named explicitly.

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?

There is no statement of when to use this tool versus tiktok_songVideos, tiktok_popularSongs, or tiktok_playlists, and no prerequisites. Usage is only inferable from the returned-field list, which is not real guidance.

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