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

Annotations already establish read-only, idempotent, closed-world safety, and the description adds substantial behavioral detail: conditional disclosure rules for writer shares, confirmation status of credits, optional audio analysis fields, and omitted empty fields. It does not discuss rate limits or lookup failure behavior for an unknown ISWC/UUID, which keeps it just short of the top mark.

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?

Trigger phrases and the core action are front-loaded, and the follow-up routing is clearly set off with an arrow. The return-value enumeration is a single long run-on clause that would read better as a list, but given there is no output schema it largely earns its space.

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 and a rich return payload, the description fully documents what comes back (credits, IPI, conditional shares, ISRCs, audio analysis, streaming links, AI origin, PICA score, licensing status) and how output is formatted. Nothing an agent needs to call or interpret it is missing.

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 the single identifier parameter already documents the ISWC format and UUID alternative, so the description's 'by ISWC or work UUID' merely restates the schema. No additional syntax, normalization, or fallback guidance is offered.

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 precise verb plus resource ('Get the details of a single listed work by ISWC or work UUID') and the 'single' scoping distinguishes it from sibling list/search tools such as directory_list_works and directory_search.

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?

Provides concrete user-question triggers ('what's the ISWC for X?', 'is this song registered?') that define when to select it, and explicitly routes follow-ups to directory_lookup_person for credited writers and directory_search_recordings for audio similarity.

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