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

Annotations already declare read-only, idempotent, closed-world behavior, so the safety profile is covered. The description adds genuine behavioral context beyond that: the enumerated refusal reasons (insufficient_data, unsupported_market, unknown_location, needs_clarification) and the instruction never to substitute a guess, plus the shape of a successful return.

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 core output promise, then the input modes, then the refusal contract; every sentence carries information. The long parenthetical on listing_id slightly blurs the structure but nothing is wasted.

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 correctly supplies the return shape (figure, band, sample size, window, above/below-market comparison) and the failure modes. It leaves some ambiguity about which of the 10 optional parameters combine legitimately outside the two stated modes.

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 70%, and the schema itself documents the key constraints (rooms required with location, listing_id exclusive, transaction_type default). The description reinforces the mode selection between location+rooms and listing_id but adds little per-parameter syntax or format detail beyond what the schema already carries.

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+resource (grounded rent or sale price estimate) and defines the two distinct subject modes: a location+rooms query and a single-listing query. An agent can tell exactly what this produces (headline figure, low–high band, sample size, window) versus what siblings like search_listings return.

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?

Clearly routes between the two invocation modes (location+rooms vs listing_id, which must be sent alone) and explains what each mode yields. It also specifies that refusals are authoritative, but never names a sibling tool or states when to prefer search_listings or get_listing instead.

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