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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so those need not be restated. The description earns credit for adding output semantics the annotations and schema do not: it returns a match count plus a page of structured records, pay is KRW per month unless stated, and null means the advert was silent — the last point is genuinely useful for interpreting results.

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: the facet enumeration comes first, the return/currency/null semantics second. The middle facet list is a dense comma run that could be trimmed since the schema already names each field, but nothing is padded or redundant at the sentence level.

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 15-parameter, all-optional read tool with no output schema and full annotation coverage, the description supplies what is otherwise missing: the shape of the response (count plus page), the currency/period unit, and the meaning of nulls. An agent can call and interpret this tool correctly from the description plus 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 description coverage is 100% and the enums are self-documenting, so the schema carries the parameter burden and baseline 3 applies. The description's facet list largely paraphrases the schema property names ('region, student age, housing, visa...') without adding syntax or defaults beyond what is already documented.

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 ('Filter') and resource ('the live LucyESL board of English-teaching jobs in South Korea') and enumerates the filterable facets, so an agent knows exactly what the tool does. It stops short of 5 because it never distinguishes itself from the sibling 'search' or 'get_job' tools, leaving ambiguity for an agent choosing among them.

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?

Usage is implied by the word 'filter' plus the facet list — an agent can infer this is for narrowing the job board by attributes. However there is no explicit when-to-use, when-not-to-use, or reference to the sibling 'search'/'get_job' alternatives, so the agent must infer the routing decision itself.

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