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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds that only public details are returned and that purchasing happens off-tool ('purchase only on the website'), which is mild extra context, but says nothing about lookup failure behavior for a bad slug.

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?

One front-loaded sentence plus a localized parenthetical; no padding or restated intent. The Korean translation duplicates the English meaning, which is defensible for locale support but is redundant for an agent parsing the text.

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 usefully enumerates the returned fields (key, BPM, formats, links), so the agent knows what to expect from the call. Combined with full annotation coverage and a fully documented single param, the definition is nearly complete; only failure/empty-result behavior is unstated.

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% and the schema even supplies a format pattern and an example slug ('afterimage'), so the single parameter is fully documented structurally. The description's 'by slug' restates rather than extends that, 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?

Specific verb+resource (get one catalog song by slug) with an enumerated preview of the payload (key, BPM, formats, links), which clearly separates it from search_songs and list_catalog_facets. It does not explicitly distinguish itself from get_song_lineage, so sibling differentiation is only partial.

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 phrase 'by slug' implies the tool is for fetching a single already-known song rather than discovering one, which is usable but left to inference. No explicit when-to-use or when-to-prefer-search_songs guidance is given, and no prerequisites are stated beyond the read-only note.

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