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

Annotations already declare readOnlyHint, non-destructive, and closed-world, so the safety profile is covered. The description adds meaningful behavior beyond that: results render in an in-chat browser where 'every result plays, in every production style,' and that pagination is available via offset. It stops short of stating result limits or empty-result behavior, but adds real value.

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?

Three sentences, front-loaded with the core capability, then the filter options, then the result behavior and pagination. No waste; every clause serves a purpose.

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?

Given no output schema and 7 parameters, the description covers the search mechanics, filter options, result presentation, and pagination. It could be more complete by noting the maximum result count or default limit, and by clarifying whether filters are ANDed or ORed, but it is solid for a search tool of this complexity.

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 50-60%, with enums for tempo and vocal and examples for mood and genre, but the description doesn't elaborate on parameter usage beyond restating the categories. The offset parameter's role in pagination is explicitly called out in the description, which is helpful, but the rest is already in the schema. Baseline 3 is appropriate given partial coverage.

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+resource ('Search Starchild's catalog of original songs') and distinguishes itself from siblings like get_song and play_song by being a semantic catalog search. The description makes clear this is the discovery entry point, not a retrieval-by-ID tool.

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?

Explains the intended query style ('describe the song in plain words') and lists optional filters, and mentions using offset for more results, which is clear operational context. However, it doesn't explicitly name which sibling to use instead when the agent already knows the song (get_song) or wants to play a specific track (play_song).

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