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

Annotations already cover read-only/idempotent/safe behavior, and the description adds useful context: it is free, needs no sign-in (auth requirement disclosed), and returns slug/name/description per item. It does not mention pagination or result-size limits, which is the only gap.

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?

Three short sentences, front-loaded with what is listed, then cost/auth, then how to consume the output. No filler.

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 compensates by describing the return shape (slug, name, sentence on what it makes) and the downstream slug usage. For a single-param, read-only discovery tool this is fully sufficient.

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 the single 'query' parameter is fully documented in-schema (including 'leave out to list everything'). The description adds nothing further about the parameter, so the baseline 3 applies.

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 (Lists) and resource (ad templates, ad features, creation modes) and even enumerates the fields of each entry (slug, name, one-sentence summary). No sibling tool overlaps this discovery role, so the agent can identify it immediately.

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?

Clearly frames the tool as the discovery step whose slugs feed 'ugcfans_make_ad as template' or 'as feature', giving the agent an explicit downstream use. It does not state when NOT to use it or enumerate alternatives, but none of the siblings compete for this job.

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