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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds useful behavioral context beyond that: the result is a fixed enumeration of 29 codes plus 10 language codes, and it explicitly states "No arguments," so the agent knows this is a cheap static lookup. It doesn't characterize output shape, but an output schema exists.

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 verb and the count of codes, followed by examples and the cross-reference. Nothing is padded and nothing needed is omitted.

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 static, no-argument lookup with an output schema present, the description supplies everything required: what is returned (29 subject fields + 10 languages), illustrative values, and the downstream consumer of those values. No gap remains that would cause a misinvocation.

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?

Zero-parameter tool, which sets the baseline at 4. The description confirms "No arguments," matching the empty schema, and it explains what the arguments of the consuming tool mean, which is more semantic value than the empty schema carries.

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?

Specific verb ("List") plus a precisely quantified resource (29 WIPO Pearl subject-field codes and 10 language codes), with concrete example values that make the payload immediately recognizable. It also names the sibling tool (pearl_search_terms) whose arguments the codes feed, so an agent can tell exactly what this does versus pearl_concept or pearl_search_terms.

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?

Explicitly ties usage to pearl_search_terms' subject_field/source_language/target_languages arguments, which tells the agent when this lookup is needed. It stops short of stating the ordering rule outright ("call this first if you don't already know the codes") and doesn't mention pearl_concept as an alternative, so it's not a full 5.

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