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

No annotations are provided, so the description carries the full behavioral burden. It does disclose the return shape (distinct values plus entry count per field), which is valuable given there is no output schema, but it says nothing about ordering, whether counts are global or filtered, or any read-only/permission guarantees.

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?

A single compact phrase that front-loads the resource and appends the count detail, with no filler. It is grammatically a noun phrase rather than a sentence, which is slightly unusual but not wasteful.

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 no annotations, the description must carry behavior on its own; it does convey the core payload (facet values with counts) but omits grouping structure, ordering, and any caveats about what the counts represent. Adequate for a simple one-parameter tool, but with clear gaps.

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% with a single enum parameter fully documented in the schema, so the baseline is 3. The description's 'catalogue' framing and field examples loosely echo the kind parameter but add no syntax or selection meaning beyond the schema's enum list.

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?

The description states a specific resource and output (every distinct value of each filterable field of a catalogue, plus entry counts), which is clearly distinguishable from lookup tools like get_entry or list_entries. It stops short of naming any sibling or explicitly framing itself as the 'enumerate filter facets' operation, so it's clear but not maximally differentiated.

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?

There is no explicit when-to-use guidance, no mention of alternatives (e.g., search_encyclopedia or list_entries), and no note about when this tool is preferable. Usage is only implied by the noun phrase 'filterable field', leaving the agent to infer the call context.

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