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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds genuine context beyond that: coverage is partial ("for many songs, a drum part"), and the response is links to drum part pages rather than song records. It still says nothing about result ordering, pagination or what happens when no match is found.

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 core capability and both search modes are front-loaded in the first two sentences. The playback/slow-down/section-loop clause and "free online" are mildly promotional rather than operational, but they are compact and still convey what the linked page offers.

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 four optional parameters, no output schema and a closed-world annotation, the description carries the right load: it explains what is returned (links to drum part pages) and the partial drum-part coverage. The only gap is that limit/pagination behavior is left entirely implicit.

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 coverage is 100%, so the baseline is 3, but the description does add meaning: "in any script (Cyrillic or Latin)" tells the agent transliteration is unnecessary, and "list songs at a given tempo" reveals that bpm works standalone since every parameter is optional. It leaves bpm_range and limit entirely to the schema.

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 names a specific verb and resource — search a library of Russian and international songs — and enumerates what is retrieved (BPM, time signature, drum part links). Its scope is unmistakable next to cajon_catalog, find_drum_schools and free_drum_tools, though it never explicitly routes the agent away from those siblings.

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?

It states the two supported modes clearly: search by artist and/or title, or list songs at a given tempo. That is real when-to-use context, but there are no exclusions, no note on when tempo-only listing is preferable to a text query, and no mention of how to combine query with bpm.

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