Zillow56 MCP Server

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

No annotations are provided, so the description carries full burden. It states the tool retrieves past sales, implying a read-only operation, but doesn't disclose behavioral traits like pagination handling (page parameter), rate limits, authentication needs, or what constitutes 'past sales' (e.g., time range, status). The mention of page parameter hints at pagination but lacks details.

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 zero waste. It's appropriately sized and front-loaded, directly stating the tool's purpose without unnecessary elaboration.

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 and no output schema, the description is minimally adequate for a simple read operation. It covers the basic purpose and key parameter (zuid), but lacks details on behavior (e.g., pagination, data format) and doesn't compensate for the absence of output schema or annotations. It's complete enough to understand what the tool does but not how to use it effectively.

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 both parameters (zuid and page). The description adds minimal value by noting zuid can be extracted from '/agent', but doesn't clarify semantics beyond what the schema provides (e.g., format of zuid, how page works). 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: 'Get agent's past sales by zuid'. It specifies the verb ('Get'), resource ('agent's past sales'), and key identifier ('by zuid'). However, it doesn't explicitly differentiate from siblings like 'agent_details_by_username' or 'search_for_agents', which might also retrieve agent information.

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 zuid can be extracted from '/agent', but doesn't specify if this is the only way to obtain it or when to prefer this tool over other agent-related tools like 'agent_reviews' or 'agents_active_listings'.

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