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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so safety is covered; the description adds value beyond them by stating no authentication is required and by scoping the return surface ('public metadata; raw audio and private manuscript text are not returned'). It does not discuss pagination, caching, or failure modes for an unresolvable song, which keeps 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?

Front-loads the core action and returned fields, then routes to alternatives, then bounds the output. Four sentences with no padding, though the 'not music analysis / does not prove listening' disclaimer slightly overlaps with the sibling-routing sentence.

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 the return-shape burden and does so at a summary level (title, creator, official page/stream, metadata, exclusions). Auth and safety are covered. It is complete enough to call correctly, though a hint about behavior when the song record is absent would close the last gap.

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 description coverage is 100% and the schema itself explains that all three optional fields are vestigial shared-schema fields to be omitted. The description adds no parameter guidance, which is acceptable here since the schema fully does the work; 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 ('Read') and resource ('public identity and rights-safe context for the Cassie Hour companion song') and enumerates the returned fields (title, creator, official page/stream, available metadata). It also explicitly disclaims what it is not ('not music analysis, does not prove anyone listened'), which separates it from siblings like inspect_musicology and inspect_listening_receipt.

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?

Names three alternatives with the exact condition that selects each: inspect_musicology for analysis metadata, search_lyrics for author-verified lyric text, retrieve_streaming_link for only the official destination. It also rules out an expected-but-wrong use case (proving listening), leaving nothing to inference.

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