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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered; the description goes further by disclosing a real behavioral trait — that completed lookups cost credits and that repeated requests may purchase the same data again. That credit/billing warning is the kind of non-obvious cost context the schema cannot express. It stops short of describing result volume, pagination, or rate limits.

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 first two sentences are useful and front-loaded, but the tail is pasted supplier boilerplate ("Apple Music Search API View Pricing Search Apple Music 1 credit per request / Actual supplier units are reported per request. Examples are not guaranteed prices.") that reads as scraped page text. Worse, it puts two conflicting cost figures side by side — "at least 10 Nexscope credits" and "1 credit per request" — which forces the agent to guess.

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, the description does at least sketch the return shape as "public result sections" by entity type, and it discloses billing, which are the two things an agent most needs here. It is still incomplete on limits, result counts, and the valid type values, and the internal credit contradiction undermines confidence in the cost model it just introduced.

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 both query and type are already documented in the schema and the baseline is 3. The description's type enumeration is redundant with the schema and actually narrower, so it adds no meaning beyond the structured field and slightly muddies it.

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 ("Searches Apple Music") and enumerates the result sections returned (artists, albums, songs, playlists, stations, music videos), which is far more informative than the title alone. It does not, however, distinguish itself from close siblings like social_apple_music_album, social_apple_music_artist, or social_apple_music_track, so an agent must infer that this is the broad search entry point.

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 sentence "Use type=song, album, artist, playlist, or all" gives operational guidance on the type parameter, but never states when to choose this search over the per-entity sibling tools or what to do with the results. The listed type values also omit station, music_video, and radio_episode that the schema allows, so the guidance is partial rather than authoritative.

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