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

Annotations already declare readOnly, idempotent and non-destructive behavior, so the burden is light, and the description still adds real context: results are scoped by the caller's identity, and the creator filter is agency-only. It does not mention pagination semantics, but the cursor parameter carries that.

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 sentences, no filler, with the visibility scope front-loaded and the agency filter following. Every clause carries information.

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 an output schema present, return values need no explanation, and pagination is covered by the schema's cursor/limit descriptions. What remains is minor: no explicit routing to media_kit_get for single-kit retrieval, and no statement of ordering.

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 all three parameters are already documented, including the agency-only restriction on creator_id. The description restates that restriction but adds no format, default, or boundary 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+resource ("List media kits") and adds a scope qualifier ("visible to the authenticated creator or agency"). It is distinguishable from media_kit_get, though it never names a sibling explicitly to reinforce that contrast.

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 one implicit usage rule — agency callers may filter to a roster creator — which tells the agent when creator_id applies. It offers no guidance on when to list versus fetch a single kit (media_kit_get) or how it relates to the template-listing sibling.

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