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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. Beyond that the description names the returned fields (name, type, price, description, preview image, links), which is genuinely useful with no output schema, but says nothing about result ordering, paging beyond the limit default, or empty-result 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?

Two sentences, front-loaded with the verb and scope, ending with the operational rule. The parenthetical font-style list is long but earns its place by supplying vocabulary for query terms. Nothing is redundant.

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 read-only 4-parameter search with no required args and no output schema, the description supplies the domain coverage and return-field list an agent needs to call it confidently. The remaining gap is that it omits the distinction between type and free_only filtering, which an agent must infer from the schema alone.

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%: query and free_only are documented in-schema while type and limit are not. The description partially compensates by enumerating the catalogue categories that type selects and by tying an empty query to type-scoped listing, but it never explains free_only ('free for personal use' beyond the schema) or limit behavior. Baseline 3 fits a half-documented 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 ('Search the FGD catalogue') and enumerates the content domain: fonts by style, the 6 font bundle, design assets and live 3D mockups. That scope makes it visibly a discovery tool, distinguishable from id-based retrieval siblings like get_item. It stops short of naming a sibling or stating the contrast explicitly.

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?

'Leave query empty to list everything of a type' gives a concrete usage rule for the browse case versus the search case, which is the main decision an agent has to make. No when-not guidance or named alternative is given, so it falls 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.