lookup_property_by_addressReturns full Zillow property data (price, Zestimate, photos, schools, taxes, agent contact, price history) for a given U.S. address. Costs 3 credits on the Zillapi account.
| Name | Required | Description | Default |
|---|---|---|---|
| address | Yes | Full street address with city, state, and ZIP. Example: '1600 Pennsylvania Ave NW, Washington DC 20500'. |
Changes observed during successful MCP inspections.
Input schema / properties / address / descriptionPrevious value: -"Full street address with city, state, and ZIP. Example: '17 Zelma Dr, Greenville, SC 29617'."New value: +"Full street address with city, state, and ZIP. Example: '1600 Pennsylvania Ave NW, Washington DC 20500'."Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the burden of behavioral disclosure. It discloses the cost (3 credits) and the return contents, which is useful. However, it does not mention what happens for invalid/non-existent addresses, potential null results, rate limits, or other operational caveats. The transparency is partial.
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 two sentences, front-loaded with the core function ('Returns full Zillow property data...') and includes a useful cost note. Every word is purposeful with no redundancy or fluff.
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 there is no output schema, the description compensates by listing the major data types returned (price, Zestimate, photos, schools, taxes, agent contact, price history) and the cost. It lacks details on error handling or not-found scenarios, but for a simple single-param lookup, this is a fairly complete description.
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?
The schema has full coverage of the single parameter 'address' with a detailed description and example. The description adds the 'U.S.' qualifier but little else beyond the schema. Baseline 3 is appropriate since the schema carries the semantic load.
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 clearly states the tool returns full Zillow property data for a U.S. address, listing specific data types (price, Zestimate, photos, schools, taxes, agent contact, price history). It distinguishes from siblings like lookup_property_by_zpid (by ID) and get_zestimate (only Zestimate) by focusing on address-based lookup.
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 implies usage when a U.S. address is available, but it does not explicitly compare to alternatives or state when not to use it. The mention of 'Costs 3 credits' is operational, not usage guidance. No clear when/when-not guidance is provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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