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 describes what data is returned (contact infos, active listings, reviews) but doesn't disclose important behavioral aspects like rate limits, authentication requirements, error conditions, or pagination behavior. The description adds some value but leaves significant gaps for a tool with no annotation coverage.

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 appropriately concise with two sentences that each earn their place. The first states the purpose and scope, the second clarifies the username parameter with a helpful example. No wasted words, though the 'PS' formatting could be cleaner.

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 provides adequate basic information about purpose and parameter semantics, but lacks details about return format, error handling, and behavioral constraints. For a tool with rich sibling relationships and no structured metadata, more completeness would be helpful.

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 username parameter. However, the description adds crucial semantic context by explaining that 'username is the profile link' and providing a concrete example with the URL relationship. This significantly enhances understanding beyond the schema's basic type information.

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 details by username' with specific examples of what details are included (contact infos, active listings and reviews etc). It distinguishes from siblings like 'agent_reviews' or 'agents_active_listings' by being more comprehensive, though it doesn't explicitly name those alternatives.

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 context through the example showing username format and URL relationship, but doesn't explicitly state when to use this tool versus alternatives like 'search_for_agents' or the more specific sibling tools. No explicit when-not-to-use guidance is provided.

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