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

Annotations already cover the read-only, non-destructive, closed-world profile, and the description adds substantive behavior: a 24-month lookback window, a minimum-5-sales gate that suppresses the verdict, a resale-only median variant, and a caveat that the result is guidance not a valuation. It stops short of describing output field units/shape or failure modes for unknown slugs.

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 decision question, then scope, then returned signals, then the gate, then the caveat and prerequisite. Dense but every clause carries information the agent needs; nothing is repeated from the schema or annotations.

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?

With no output schema, the description does the work of sketching the return payload (verdict, percentile, resale-only median, recent sales) and the threshold behavior. It is nearly complete for a read-only lookup, though the exact result fields and what happens on an unknown slug or zero-sales building are left implicit.

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 only 50% – bedrooms and askingAed are documented in-schema for their meaning and ranges. The description compensates for the two undocumented slug parameters by naming them as the pair returned by search_locations, and reinforces that 'bedrooms' defines the layout comparison cohort.

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 and resource: compares an asking price against registered DLD sales of the same bedroom layout in the same building over 24 months, and enumerates the outputs (verdict vs median, percentile, resale-only median, recent sales). It is clearly distinct from the rent-focused sibling check_asking_rent and from the aggregate get_building_stats.

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 frames itself as a negotiation guide rather than a valuation, states the prerequisite that the communitySlug + buildingSlug pair comes from search_locations, and gives a when-not condition (no verdict below 5 backing sales). No explicit contrast with check_asking_rent or get_price_history is given, so a 4 rather than a 5.

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