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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, and the description is consistent with them while adding useful behavioral context: the operation is non-persistent (no account save) and produces no file artifact. It does not describe refresh/statefulness of the preview or any limits, so it's solid rather than exhaustive.

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?

Three short sentences with no filler; the core purpose and the design-type list come first, followed by the two constraints and the font prerequisite. Nothing is repeated from the schema.

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?

For a one-parameter tool with a deep nested schema, 100% schema coverage and an output schema (so return values need not be explained), the description covers purpose, constraints, and the font dependency. The main gap is the workflow link to save_design/export_design (e.g. what to do with the result), which is implied rather than stated.

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 the nested settings object is fully documented and the baseline is 3. The description adds value beyond the schema by naming the informal design variants (keychain, pet tag, cake topper, sign, flip) that correspond to baseMode values, and by pointing at list_design_options as the authoritative source for the font URL.

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 gives a specific verb pair ('Configure and show an interactive 3D preview') plus an explicit resource list (name, keychain, pet tag, cake topper, sign, two-name flip design). It also differentiates itself from siblings by ruling out saving and exporting, so an agent can distinguish it from save_design and export_design without opening a 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 states two important exclusions ('Does not save to an account or export a file') which implicitly route persistent/finalizing work to save_design and export_design, and names list_design_options as the source of valid font URLs. It stops short of explicitly saying 'use this tool when you want a preview before saving', so it's clear but not fully prescriptive about when/when-not.

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