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

Annotations already declare read-only, idempotent, non-destructive; the description adds value beyond them by disclosing cost ('Free: nothing is charged'), result count and ordering ('up to 4 options, best first'), and the required conversational follow-up before invoking use_skill.

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-loads the purpose and workflow compactly with no filler, though the trailing parenthetical about list_my_skills and the exclusion sentence make it denser than strictly necessary.

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 conveys what comes back (named styles with preview video or picture), how many and in what order, that it's free, and what to do next—everything an agent needs to call it and handle the result.

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%, so intent, type enum, and limit bounds are already documented. The description's examples of result kinds loosely echo the enum values but add no syntax or format detail beyond the schema; 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 and resource ('find ready-made skill presets'), enumerates concrete result kinds (launch videos, slide decks, landing pages, editorial images), and explicitly distinguishes itself from the sibling list_my_skills. An agent can immediately tell this apart from use_skill and list_my_skills.

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?

Gives the full workflow (show options with preview links, ask the user, then call use_skill with the slug) plus explicit negative guidance: not for bookings, shopping, live data, or tasks PopNow can't do. Both when-to-use and when-not-to-use are stated.

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