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

Annotations already cover read-only, idempotent, non-destructive, closed-world, so the bar is lower; the description nonetheless adds real behavioral context: no manuscript text is returned, personal listening is not established, and spoiler-filtered/source records are bounded by the grant. The phrasing of the last sentence is somewhat vague, keeping it short of 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?

Three front-loaded sentences that lead with the core action and mode distinction, then alternatives, then constraints. Dense but mostly earned; the closing sentence on spoiler-filtered records is the weakest and slightly redundant.

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 carries return-value guidance and does so adequately (relationship context vs. indexed evidence, no manuscript text). Auth prerequisites, mode boundaries, and sibling alternatives are all present; only the exact shape of returned evidence is left unpinned.

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% and each parameter already carries a detailed description, including query's mode-dependent behavior. The description restates the query semantics but adds no format or syntax detail beyond the schema, so the baseline 3 applies.

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 (compare) and resource (public song/story relationship metadata), and distinguishes its two operating modes (public vs. authenticated grant). It also explicitly names what it is not: get_song_dossier for song identity alone and find_audio_motif for audio-segment evidence.

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?

Explicitly routes the agent: use this for song/story relationship comparison, get_song_dossier for identity, find_audio_motif for audio segments. It also states the condition that switches modes (no auth = public context only; authenticated current music_retrieval grant = indexed evidence via query).

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