library_find

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

With no annotations and no output schema, the description carries the full behavioral burden. It hints that the return concerns membership and stored spelling, but says nothing about matching semantics (exact vs fuzzy), what happens on a miss, whether the query is read-only, or what the response shape is.

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?

A single front-loaded sentence with no filler; the purpose and the unusual spelling output are both packed in efficiently. Slightly terse given the gaps it leaves elsewhere.

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 lookup with no annotations or output schema, the description conveys the core purpose and the noteworthy return aspect (canonical spelling). It still omits matching behavior, failure behavior, and routing against the sibling search/library tools.

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?

There is one required parameter, 'query', with 0% schema description coverage, so the description must explain it. It only indirectly implies the query is a song identifier; it does not say whether it should be a title, 'artist - title', or a free-form string, nor how matching is performed.

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 gives a specific verb ('check') and a specific resource ('user's saved YouTube Music playlists'), plus a distinctive secondary output ('how it is spelled there'). It is clearly not a playback or search-catalog tool, though it never names the siblings (search_music, library_refresh) it must be distinguished from.

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 use case is implied: reach for this when you need to know whether a track is already saved rather than to find or play it. However, it never states when to prefer it over search_music or library_refresh, and gives no exclusions or prerequisites.

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