zillow_property: GET /

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

With no annotations provided, the description carries the full behavioral burden and it largely meets it. It discloses the rich return payload, the optional email extraction behavior, the note that email extraction increases cost, and that it treats the URL or zpid as the key. It does not discuss errors, auth, or rate limits, but for a read-style data fetch the behavior is otherwise well disclosed.

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?

The description is front-loaded with the core purpose and then uses a long, valuable list of return fields. It is information-dense but not bloated; each item supports an agent understanding of output. It is not as crisp as a two-sentence version, hence a 4 rather than a 5.

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 that there is no output schema and no annotations, the description compensates by listing the major return categories, mentioning input composition, and naming target use cases. The agent can infer what a successful invocation yields. It does not fully specify failure modes or zpid format, but the essential call-and-response context is largely complete.

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 parameter meaning is already fully documented in the schema. The description adds mild context by framing extractAgentEmails as 'optional agent email extraction' and tying the URL to a full page fetch, but it does not substantially add syntax or domain meaning beyond the schema.

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 uses a specific verb ('Fetches') and a precise resource ('full Zillow property page by URL/zpid'), then enumerates the concrete data returned. It distinguishes itself from the sibling listing tool by focusing on a single property page rather than real estate listings, even though the sibling is not explicitly named.

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?

The description says exactly when to use this tool: 'Use for valuation models, CMA generation, investor underwriting, rental yield analysis, and enriching buyer/seller agent assistants.' This is clear context and use-case targeting. It does not explicitly exclude the sibling tool or state when not to use it, so it stops short of a full 5.

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