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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds value by disclosing the returned content (styles, formats, licencing summary, price, checkout_url), which compensates for the absent output schema; it does not mention behavior on an unknown id, which is the only notable gap.

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?

One sentence, front-loaded with the purpose before the field enumeration, with no filler. The long trailing field list is dense but each item is informative about the payload, so it earns its place.

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 single-parameter read tool with full schema coverage, annotations, and no output schema, the description covers purpose, id provenance, and return contents. An agent has everything needed to select and invoke it 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% and the single id parameter is well documented with examples, so the baseline is already high. The description adds provenance by noting ids come from search_catalog and that ids span heterogeneous item types (font, bundle, asset, mockup), which is meaning beyond 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?

The description gives a concrete verb-plus-resource ('Full details of one font, the bundle, an asset or a mockup by id') and enumerates what comes back, so an agent knows exactly what this returns. It does not explicitly contrast itself with siblings like get_licence, even though it returns a 'licence summary', leaving mild ambiguity about when to prefer the dedicated licencing tool.

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?

The parenthetical '(from search_catalog)' implies the correct upstream flow — find ids via search_catalog, then fetch details here — but it is embedded rather than stated as guidance. There is no explicit when-not or alternative routing, so usage is inferred rather than instructed.

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