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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is covered. The description adds a useful behavioral fact — that future videos fall back to the transcription — but does not state that existing custom lyrics are discarded, whether the revert is reversible, or which permission is needed.

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 with no filler, and the effect is front-loaded. It is efficiently sized, though the opening clause is metaphorically worded rather than action-oriented.

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 one-parameter tool with no output schema and full annotation coverage, the description is close to adequate, but as a destructive operation it should state clearly that the custom lyrics are removed and that the change is effectively permanent.

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?

With a single parameter and 100% schema description coverage, the schema already documents song_id. The description adds nothing about the parameter (no id format, source, or constraints), so the baseline 3 applies.

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 conveys the effect (reverting to transcribed words) rather than naming the action: it never says it removes or clears the song's custom lyrics. Combined with the tool name and title the intent is inferable, but the description alone is vague and gives no differentiation from siblings like set_song_lyrics or create_lyric_video.

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 when-to-use or when-not-to-use guidance and no named alternative. The only context offered is a downstream consequence ('videos made from then on show the words as transcribed'), which is not usage guidance.

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