Zillow56 MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. 'Get lender details' implies a read-only operation, but it does not specify if authentication is required, rate limits apply, or what the output format looks like. For a tool with zero annotation coverage, this is a significant gap in transparency.

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 a single, efficient sentence with no wasted words, making it easy to parse. However, it is under-specified rather than concise, as it lacks necessary details for full understanding, but it is structured well for its brevity.

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 the tool's simplicity (1 parameter, no output schema, no annotations), the description is incomplete. It does not explain what 'lender details' includes, how to interpret the output, or any behavioral aspects like error handling. For a tool with no annotations or output schema, more context is needed to be fully helpful to an agent.

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 input schema has 100% description coverage, with 'screenName' documented as 'Example value: mortgagecapitalpartners'. The description does not add any meaning beyond this, such as explaining what a 'screenName' represents or its format. Given the high schema coverage, a baseline score of 3 is appropriate, as the schema handles the parameter documentation adequately.

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 'Get lender details' states a clear verb ('Get') and resource ('lender details'), which provides a basic understanding of the tool's function. However, it lacks specificity about what 'details' includes (e.g., contact info, loan products, ratings) and does not distinguish it from sibling tools like 'lenderreviews' or 'lendersearch', making it vague in comparison.

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 offers no guidance on when to use this tool versus alternatives. It does not mention prerequisites, such as needing a 'screenName', or suggest when to choose this over sibling tools like 'lenderreviews' for reviews or 'lendersearch' for finding lenders, leaving the agent without usage context.

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