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

Annotations already declare readOnlyHint=true, openWorldHint=true, and idempotentHint=true, so the safety profile is covered. The description adds useful context about the data content (school name, level, grades, distance, rating) but does not disclose any further behavioral traits such as return shape, behavior when no schools are assigned, or data freshness.

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 compact sentence that conveys the core purpose and the main returned fields without redundancy. Every element earns its place and the key association with a specific home is front-loaded.

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 simple read-only tool with only one required parameter and no output schema, the description explains what the caller will receive: school assignments with name, level, grades, distance, and rating. It is complete enough for an agent to know when and how to use it, though it could note that results are tied to a single zpid or address potential absence of assigned schools.

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%, with zpid and expand already well documented in the schema. The description does not need to add parameter detail, and it does not add anything beyond the schema, 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 the resource clearly: schools assigned to a home, and enumerates the returned fields (name, level, grades, distance, GreatSchools rating). It is distinguishable from siblings like zillow_scores or zillow_property_facts, though it does not explicitly contrast itself with them or use a direct verb like 'gets'.

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 context is implied: use this when you need the schools assigned to a particular home, identified by zpid. However, it provides no explicit when-to-use guidance, no exclusions, and does not mention alternatives among the many sibling tools.

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