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

With no annotations, the description carries the full burden and does well: it discloses the data source (MOLIT), coverage since 2006, daily updates, request cost ($0.0045 USDC via x402 on Base or Solana), and the output field set. It omits rate limits and pagination, but covers the major behavioral traits an agent needs before paying for a call.

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-loads the usage condition, then follows with compact Data/Input/Output/Example/Price blocks. Every sentence carries information an agent needs, with no filler.

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?

Given two required parameters and no output schema, the description fully specifies output fields (contract date, complex names, area, floor, build year, KRW/USD price, price per m2, deal type, cancelled flag). It also covers data provenance, freshness, error behavior, and payment cost.

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 both parameters (region, month) are already fully documented in the schema, including formats and examples. The description reinforces this with an example query and a Gangnam-gu code, but adds no semantics beyond the schema — baseline 3.

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 — actual apartment sale prices in a South Korean district for a given month — and names the data source. Its sibling kr_apartment_trades_summary is a summary tool, and this description's emphasis on actual per-deal trades distinguishes it.

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?

Opens with a clear 'Use when you need...' statement and lists concrete scenarios (property research, valuation, comps). It does not explicitly name the sibling summary tool or state when not to use this tool, so it stops short of full routing guidance.

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