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. It describes the output ('comprehensive snapshot and historical trends') but lacks critical behavioral details such as data freshness, rate limits, authentication needs, error handling, or whether it's read-only. For a tool with no annotations, 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, well-structured sentence that efficiently conveys the core purpose without redundancy. It's appropriately sized and front-loaded, though it could be slightly more concise by trimming phrases like 'using metrics aligned with'.

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 no annotations, no output schema, and a single parameter with full schema coverage, the description is incomplete. It lacks details on output format, behavioral traits, and usage context, making it inadequate for an agent to fully understand the tool's operation and limitations.

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 the schema already documents the 'location' parameter with an example. The description adds no additional parameter semantics beyond implying regional scope, which is minimal value. Baseline 3 is appropriate as the schema does the heavy lifting.

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's purpose: to deliver a comprehensive snapshot and historical trends of the housing market using ZHVI metrics. It specifies the verb ('delivers') and resource ('housing market in a given region'), making it understandable. However, it doesn't explicitly differentiate from sibling tools like 'market_data_rental_market_trends' or 'zhvi_range', which appear related, so it misses full sibling distinction.

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 provides no guidance on when to use this tool versus alternatives. It mentions the ZHVI framework but doesn't specify contexts, exclusions, or compare to sibling tools like 'market_data_rental_market_trends' or 'zhvi_range', leaving the agent without usage direction.

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