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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds a genuinely useful constraint beyond that: only job-ad terms are available in 20 languages, all other terms come back in English or Dutch for the assistant to translate. It says nothing about response length or format, so this is solid but not rich.

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?

The core capability is front-loaded in the first clause; the example terms and language list are long but function as capability specification rather than filler. The 20-code enumeration is the one slightly bloated element, though it does document real coverage.

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 two-parameter lookup with no output schema, the description covers what is returned (an explanation in a specified language) and the language limitation that would otherwise cause a failed expectation. Only the shape/length of the returned explanation is left unstated, which is minor here.

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 the baseline would be 3, but the description adds meaning the schema does not: it clarifies that `language` is only honored for job-ad terms and that other domains fall back to English/Dutch. It also implicitly confirms `term` accepts either the Dutch word or its English meaning, matching the schema note.

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 ("Explains Dutch terms") and narrows the scope to tax letters, job ads, housing, health and government, with concrete example terms. This clearly separates it from every sibling, which are all calculators/planners rather than a glossary lookup.

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 enumerated domains and example terms make it obvious when the tool applies (the user hit an unfamiliar Dutch term). It stops short of an explicit when-not clause or naming a sibling alternative, but with a glossary tool among calculation tools the trigger condition is unambiguous.

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