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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds useful domain context, specifying monthly Zillow ZHVI/ZORI series and metro/state geography, but it does not add behavioral details beyond the annotations, such as pagination, missing-data behavior, or rate limits.

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?

It is a single, front-loaded sentence that states the operation, the two metrics, the granularity, the geography, and the use case. Every clause carries information and there is no redundant or filler text.

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?

The tool is read-only with a simple three-parameter schema that is fully documented, and no output schema exists. The description adequately covers what the tool returns (a monthly time series) and the supported metrics, but it could be slightly stronger with a note about default month behavior or the nature of the series beyond the schema.

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 defines metric values, month defaults and maximums, and accepted region formats. The description echoes the metric and region concepts but adds no syntax, constraints, or examples beyond what the schema provides, so the baseline of 3 is appropriate.

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 (Get), resource (monthly time series of home values or rents), and scope (metro or state), making the core purpose clear. It does not, however, differentiate itself from nearby siblings like realestate_home_values or realestate_rents, leaving the agent to infer why this combined trend tool should be chosen over those.

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 phrase 'to chart or analyze the trend' implies the intended use case, so usage is more than absent. But there is no explicit when-to-use guidance, no when-not-to-use condition, and no named alternative among the many realestate siblings.

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