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

Annotations are minimal, and the description carries the full behavioral burden: bills per returned row while subject_property is non-billable, lists exactly what is returned, and states what is never returned (retired/raw ids, REST debug keys). The cost/loop warning is exactly the kind of side-effect disclosure an agent needs and cannot get from annotations.

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?

Purpose and required cost caveat are front-loaded, but it is a dense single paragraph mixing product-roadmap notes (CompDistance/ZipFive 'accepted engineering deferral to v2') that do not help an agent select or invoke the tool. That internal detail dilutes otherwise useful content.

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?

Despite no output schema, the description enumerates the return shape (results[], subject_property, returned_count, total_cost, radar_id, comp_type, fields, related_tools[]) and covers cost, defaults, and alternatives. For a 13-parameter billed tool, nothing material an agent needs is missing.

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?

With 0% schema description coverage the description must compensate, and it does for most params: comp_type semantics (sales default vs listings), limit default 10 with 1-50 bound, fields fieldset ids and default, transfer_types sales-only / listing_types listings-only, and the subject-override params. It leaves the exact semantics of beds/baths/sqFt/lotSize/yearBuilt overrides thin and uses snake_case names that do not exactly match the camelCase schema keys.

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 ('Fetch billable comparable Property rows for one subject Property by RadarID') and its scope. An agent can distinguish it from get_property_details (scalar subject fields) and get_property_transactions (recorder history) without opening any schema.

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 routes to siblings ('Use get_property_details... and get_property_transactions...') and states a when-not condition ('Do not loop this tool across many RadarIDs unless the user explicitly intends the multiplied per-row cost'). Nothing is left to inference about when this is the right call.

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