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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so behaviour is largely covered structurally. The description still adds real value beyond them: it discloses data provenance ('computed from the live listings'), the statistical caveat that each median reports its underlying advert count, and a CC BY 4.0 licensing/attribution requirement. No return format or caching/freshness detail, so not a 5.

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?

Front-loaded with the scope, then a compact metric list; the sample-size caveat and licence are tacked on as short clauses that each carry information. It reads as fragments rather than full sentences, but no clause is filler and it is well under the length where truncation risk matters.

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?

There is no output schema, so the description must carry the return shape, and it does by naming every metric returned plus the per-median sample size. What is missing is any hint about output structure/format or how fresh the underlying listings are, which an agent deciding between this and market_stats would want.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly implies a single global aggregate with no filtering arguments, consistent with the empty 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 names the specific resource (English-teacher salaries in South Korea) and enumerates the exact statistics produced: median, quartiles, region, employer type, effective hourly pay, disclosure rates, housing. That is far more than a restatement of the title. It stops short of 5 because it never distinguishes itself from siblings like market_stats or disclosure_stats, which plausibly cover overlapping ground.

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?

Use is implied by the scope statement – it is the tool for pay figures rather than individual listings – but there is no explicit 'use this when…' or exclusion against market_stats or disclosure_stats, despite obvious topical overlap. The agent has to infer routing from the sibling names alone.

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