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

With readOnlyHint and openWorldHint already declared, the description still adds material behavior: the $0.002 USDC per successful call cost, the x402 payment rails (Base, Solana, Arc), the guarantee that failed calls are not charged, and per-page limits. This is exactly the kind of cost/auth context annotations cannot express. It stops short of covering rate limits, caching/freshness of MLS data, or partial-failure behavior.

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 is front-loaded, which is good, but the middle sentence is a ~20-field run-on enumeration of listing attributes that duplicates the output schema and consumes most of the description's length. The high-value content (filters, pagination, price/payment) is buried around that list.

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?

An output schema exists, so return shape needn't be explained (the field list is redundant rather than necessary). For a paid, paginated, open-world scraper the description covers cost, payment, charge-on-success-only, page cap, and the fact that filters apply per page — enough for an agent to call it correctly. Freshness of MLS data and empty-result behavior remain unstated.

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%, so every parameter already documents itself (including the notable 'filters this page' caveat on type/minBeds/minPrice/maxPrice). The description merely restates 'Filter by type, price range and minimum bedrooms' and the 200-per-page cap without adding syntax, edge cases, or default behavior beyond the schema. Baseline 3 applies.

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 opens with a concrete verb+resource+scope: 'US homes for sale from Estately (regional MLS data) for a city'. The named source (Estately) and geographic scope distinguish it from the many other real-estate listing siblings such as Zillow or Redfin. It does not, however, explicitly state when to prefer it over those alternatives, leaving the differentiation implicit in the brand name.

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?

Filtering capability (type, price range, minimum bedrooms) and pagination ceiling ('up to 200 listings per page') are stated, which implies how to narrow a query. There is no explicit when-to-use vs when-not guidance, no mention of what to do when a city returns zero listings, and no alternative tool is named despite ~60 real-estate siblings.

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