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

Annotations already mark this as read-only, idempotent, and non-destructive. The description adds useful behavioral context: ranking by goal and section, the made_recently preference, and an alternate bulk endpoint. The made_recently reference is somewhat cryptic but still extends beyond the annotations.

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?

The description is reasonably compact but includes stylized, somewhat tangential phrasing like 'Siren picks one when you don't' and the cryptic 'made_recently' rule. It is front-loaded with the core concept, but not every sentence earns its place.

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 read-only, well-schematized listing tool with an output schema, the description covers ranking behavior, section shelves, downstream usage, and an alternative for getting the whole library. Pagination detail is left to the schema, which is acceptable here.

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?

The input schema already documents all seven parameters with 100% coverage. The description adds meaning by explaining how goal and section affect ranking, how to use a returned style id downstream, and when to prefer the full-file endpoint. This goes beyond simply restating 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?

The description clearly identifies the tool as the style library and describes it as returning ranked, paginated styles. It distinguishes the resource (painted stills/styles) from sibling list_* tools, though it uses stylized language rather than an explicit 'list styles' statement.

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?

The description gives practical guidance: pass section and the human's goal, prefer section + page or the styles.md file for full-library needs, and use the returned style id in create_campaign. It does not explicitly compare against alternative sibling tools, but the usage context is clear.

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