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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so safety is covered. The description adds genuinely new behavioral facts: sort order ('newest first'), the shape of each returned record, and cost ('Free'), which matters for an agent deciding whether to call it. Pagination behavior across page/pageSize is not disclosed.

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 plus a one-word cost note; the resource, ordering, payload and intended use are all front-loaded with zero filler. Every sentence carries distinct 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 no output schema, the description usefully lists what each asset record contains, and annotations cover safety, so the agent has enough to call this correctly. The main residual gap is pagination/total-count behavior for a list that can be long, which is undocumented in both schema and description.

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 50%: tag and type are documented in the schema, while page and pageSize rely on defaults and min/max bounds only. The description adds no filtering or paging semantics itself ('newest first' only hints at ordering), so it does not compensate for the coverage gap, though the schema carries enough for the documented half.

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 uses a specific verb and resource ('List the user's Voidless assets') and even enumerates the returned fields (id, type, prompt, tags, frame/animation counts) plus ordering ('newest first'). It does not explicitly contrast with get_asset for fetching a single asset, so sibling differentiation is implied by 'list' rather than stated.

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?

'Use this to find an asset to animate, rotate or edit' gives a concrete downstream purpose, linking it to siblings like animate_sprite or rotate_sprite. However, it names no alternative (e.g., get_asset) and gives no when-not-to-use or prerequisite guidance.

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