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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the 'Read-only' sentence is partly redundant, but the description adds real behavior beyond them: newest-first ordering, one-page-at-a-time with nextCursor returned and fed back as cursor, and that a finished build surfaces as a saved design. It does not contradict the annotations.

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-loaded with the core action and result shape, and the paging and scope sentences earn their place. The trailing sentence about credits/payments is scope disambiguation rather than tool mechanics and adds a little bulk, but overall it remains dense and readable.

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 not be described; the description still covers ordering, result contents, pagination mechanics and scope boundaries. Nothing material is missing for an agent to call this correctly.

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% so baseline is 3, but the description adds meaning on top: 'query searches by name' and the explicit nextCursor -> cursor pagination contract, which clarifies how the parameters compose across calls. Only limit is left solely to 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 and resource ('List one page of the person's saved iter0 designs'), plus ordering ('newest first') and what each entry contains (name, link, previews). It also distinguishes scope from siblings like get_design by framing this as the find-a-named-design / check-build-finished lookup, and explicitly excludes adjacent domains like design advice, hosting and domains.

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 concrete when-to-use cases: finding a design the user names (with an example) or checking whether a started build has finished. It also names when-not-to-use territory (general design/colour/logo/branding advice, hosting elsewhere, domains, payments), leaving little to inference.

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