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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds value beyond that by naming the returned fields (title, genre, mood, url, ref_id) and the pagination mechanism, plus the underlying endpoint. It stops short of stating page size or rate limits, so not a 5.

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?

Four compact sentences, no filler, with the resource and scope front-loaded and each remaining sentence carrying a distinct routing or return-value fact.

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 compensates by enumerating the returned fields and the pagination cursor; with annotations covering safety, the only remaining gap is page size, which is minor for a list tool.

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 baseline would be 3, but the description adds real meaning the schema lacks: mood/genre are tags sourced from mureka_list_styles, and last_id is specifically the previous page's cursor. This cross-tool semantics is what the flat schema strings cannot convey.

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 ('List Mureka's library of 30-second reference tracks') with scope and optional filters. It also explicitly distinguishes itself from mureka_list_files ('Your own uploads are listed by mureka_list_files') and mureka_list_styles, so an agent can tell the three apart without opening any schema.

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?

Gives explicit routing: use tags from mureka_list_styles to filter, use the returned ref_id in mureka_create_song_with_lyrics or mureka_create_instrumental, use mureka_list_files for own uploads, and pass last_id for the next page. When-to-use and when-to-use-something-else are both covered.

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