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

Annotations already establish readOnly, idempotent, non-destructive, and closed-world behavior, so the bar is lower. The description adds two pieces of genuinely new context: the returned fields (not covered by an output schema) and the cost signal 'Free,' which no annotation conveys.

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: the purpose and return contents come first, the create_short handoff second, and the cost note trails. Every clause carries information with no padding.

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 usefully names the fields returned and flags the zero-cost nature, and annotations cover the safety profile, so an agent has what it needs. Remaining minor gaps (pagination, exact return shape) are not critical for a free read-only list tool.

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% and both parameters (tool, locale) are documented in the schema with enums, so the schema carries the semantic burden. The description adds nothing about the tool/locale filters, so the baseline 3 is appropriate.

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 ('List') and resource ('niche templates'), then enumerates concrete categories (talent show auditions, haircut transformations, etc.) and the fields returned (tool, genre, default settings, suggested trend searches). An agent can tell exactly what this returns and, via the create_short cross-reference, where it fits among siblings like list_caption_styles.

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 tells the agent the downstream workflow: 'Pass a template id as template_id to create_short to apply its defaults,' which clarifies when this tool is useful (as a discovery step before create_short). It does not state exclusions, but no competing template-listing alternative exists among the siblings, so the practical gap is small.

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