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

Annotations already cover read-only/idempotent/non-destructive status, but the description adds meaningful behavior: no account required, no cost, return fields including ids and facets, and the recommended next call. This is richer than the structured hints alone.

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 key value proposition, then scope, return shape, and the generation-vs-catalog workflow. Every sentence contributes without repetition.

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 still explains the returned fields and facets, covers the no-auth/no-cost context, and provides the routing step to get_item_source. An agent has enough to select and invoke it correctly.

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 83%, so most parameters are already documented. The description reinforces the kind categories and points to facets for category/tag narrowing, but does not add syntax or format detail beyond the schema.

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: search the three.ws ready-made asset catalog. It enumerates the three asset libraries and distinguishes itself from sibling generation tools by positioning catalog search as the pre-generation check.

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?

Explicitly says when to use it ('before generating anything') and why ('if the catalog already has the prop or character, dropping it in is instant and free where generating one is not'). It also names the follow-up path to get_item_source.

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