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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety needs no repeating. The description adds real behavioral value by disclosing the shape of the returned content (venues, recommended extras, FAQ, benchmark rate) and the conditional 'where one exists', warning the agent that a rate may be absent. A note on what happens for an unknown slug would complete it.

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?

Two tight sentences: definition first, actionable use cases second, with zero filler. No repetition of annotations or schema.

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 simple read-only two-parameter lookup with no output schema, the description carries the return-content burden well by naming what detail fields come back and that rates are optional. It is only slightly incomplete in not covering the 'requisites' and 'profile-tags' sets it can also retrieve.

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 both parameters are documented in the schema, including the enum values for 'set', so baseline is 3. The description adds little parameter-level meaning — it does not explain how 'set' changes the result or what a slug looks like beyond what the schema states.

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+resource: it returns 'the detail behind a reference value' and enumerates the detail types (venues, extras, FAQ, rate). This is clearly a single-item lookup, so it is distinguishable from list_reference, though the description never names that sibling. The title narrows scope to genre/occasion/extra but omits the 'requisites' and 'profile-tags' sets present in the enum, leaving a small mismatch.

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 concrete usage contexts ('what does a wedding DJ actually do', 'what is an MC add-on'), which tells an agent when this tool is the right call rather than inventing an answer. It stops short of explicit exclusions or stating that a slug must first come from list_reference — that prerequisite lives only in the schema.

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