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

Annotations already cover read-only, open-world, and non-destructive behavior. The description adds useful context beyond those annotations: it discloses the 5-credit cost per successful call, lists returned fields, and notes that the MCP response is a compact view.

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 front-loaded with the core purpose and then adds only useful details: output fields, cost, and compact MCP return format. There is no redundant restatement of the tool name or schema beyond what helps an agent decide to call it.

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?

For a two-parameter search tool with annotations and no output schema, the description supplies enough return-value context, cost information, and usage framing for an agent to call it correctly. Nothing critical is missing.

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 URL and results parameters are already well documented in the schema. The description mentions Zillow search URLs generally but does not add parameter-level detail beyond what the schema provides.

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 states a specific verb and resource: searching Zillow real estate/property listings via Zillow search URLs. It also distinguishes the tool from generic page scraping, so an agent can tell it apart from siblings like scrape_page or search_web.

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?

It clearly frames the use case as US housing research and implies using this instead of generic page scraping. However, it does not explicitly name alternatives such as search_places or scrape_page, nor does it state when not to use this tool.

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