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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered; the description adds genuinely new behavioral context: sort order (newest first), the meaning of `total` as a full match count ('the user may have hundreds'), the pagination termination condition, and the read-scoped API key requirement. It stops short of rate limits or error behavior.

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?

Four dense sentences, front-loaded with the resource and ordering, then pagination, then filtering, then auth. Every clause carries information that maps to a parameter or a caller decision; 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 usefully compensates by explaining `total` and `nextOffset`, the two return fields an agent must act on. It only partially covers the returned design objects ('with their links'), leaving the rest of the design payload shape implicit, which is the one gap for a list tool of this complexity.

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 already 100%, so the baseline is 3. The description goes beyond the schema by giving concrete example format slugs ('slipcover', 'vhslabels') and clarifying that `query` matches the movie/album title, not just the design name. It adds useful disambiguation the schema's terse one-liners lack.

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 opens with a specific resource and scope: 'The user's saved designs, newest first, with their links.' That verb-implicit listing is clearly distinguishable from siblings like list_uploads, list_decals, and list_formats, which cover different resource types. An agent can route to this tool without opening the schema.

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?

It gives concrete when-to-use guidance for filtering ('Filter by `format` ... or `query`') and a full pagination recipe ('page on with `offset` = `nextOffset` until it is null'), plus the auth prerequisite ('Needs an API key with read'). It does not name an alternative tool (e.g. get_design for a single design), which keeps it short of a 5.

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