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

Beyond annotations (readOnlyHint=true), the description discloses project-scoped behavior, returns project identity with result, candidate link ordering, version-selection criteria (artist's own/'- Topic' channel, no covers), and the need to disclose licensing limitations. This is rich context not in annotations.

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 description is long but every sentence adds value: scoping, purpose, selection rules, follow-up steps, and caveats. It is front-loaded with PROJECT-SCOPED and then the core purpose. Some redundancy exists but it remains organized and purposeful.

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, the description explains that it returns candidate links best-guess first and describes the pick criteria, but it does not specify the exact structure of the result (e.g., fields or error handling). Overall it is quite complete for agent use, but a little more on return format would make it fully self-contained.

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 covers project_id well with a detailed description, but query has no schema description (50% coverage). The description compensates by explaining query is the named song, adding meaning beyond the bare schema. However, it could be more explicit about query format.

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 clearly states the tool finds web links for a specific named song, with an example ('add Blinding Lights by The Weeknd'), and explicitly contrasts it with generic catalog scenarios. This distinguishes it from siblings like add_music or fetch_url.

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 description explicitly states when to use it (named songs), when not to (genre/vibe requests should ask for user-supplied file/link), and what to do after (fetch_url with as_kind='music'). It also warns about licensing verification, giving clear decision guidance.

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