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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description still adds useful behavior: it returns private items the caller owns, it is ordered newest first, and it requires an authenticated session. Return format and pagination behavior are left unstated.

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 zero filler. The core scope (own songs, newest first, includes private) is front-loaded ahead of the auth requirement.

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 an output schema present and annotations covering the safety profile, the description needn't explain return values. Auth and result scope are covered; only pagination semantics are missing for a tool whose whole job is a paged list.

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 only 50% — page_size documents its default but page has no description at all — and the description adds nothing about how paging works, whether page defaults exist, or how results are bounded. It does not compensate for the schema gap.

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?

States a specific verb and resource with meaningful scope modifiers: the signed-in person's songs, newest first, including private ones. That distinguishes it clearly from search_songs and list_music_boxes, though no sibling is 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?

"Requires signing in" gives one real prerequisite, but the description never says when to prefer this over search_songs or get_song, nor what it excludes. Usage is implied by the 'my songs' framing rather than stated.

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