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

Beyond the readOnlyHint/idempotentHint annotations, it discloses that nothing is sent, that each suggestion carries the reasons it matched, that the total listed-work count is returned, and the precise conditions for an empty result (work not listed or owner not taking enquiries). That is materially more than the annotations provide.

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-loaded with the trigger and packed with decision-relevant detail, with no filler. The telegraphic fragments ('→ then:', 'with the user's go') are efficient but verge on run-on, costing a point on structure.

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?

For a two-parameter read tool with no output schema, the description covers what comes back, the matching rationale, the empty-result conditions, and the exact next tool to call. Nothing an agent needs in order to call it and act on results 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%, so work_id and limit are already documented. The description only echoes the ceiling ('up to 9') without adding format or semantics the agent needs beyond the schema, so 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 and resource: returns up to 9 of the SAME owner's other listed works that share this work's topics, genre or tempo. It explicitly excludes another owner's works, so the agent can distinguish it from sibling lookups like directory_lookup_work or 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?

Gives the exact user phrasings that should trigger it ('does this owner have anything similar?', 'any other songs like this from them?'), the typical context (they are asking about licensing), and the follow-up path: offer results, and only add to directory_send_licensing_enquiry's also_work_ids if the user explicitly says yes.

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