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

Annotations already provide readOnlyHint and idempotentHint, and the description adds valuable behavioral context: the ranking basis (past-year sales) and the specific fields returned. It does not mention pagination or list limits, but the safety profile is already covered by annotations.

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?

Two short sentences carry the full product concept with no filler. The key ranking idea and output contract are front-loaded, and the final phrase is memorable rather than redundant.

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?

With no output schema, the field list in the description is a useful substitute for return-value documentation. The only weakness is the slightly ambiguous 'sales in this price range,' but overall the description plus schema and annotations give an agent enough to call the tool correctly.

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?

The input schema fully documents both zpid and expand, so the description does not need to repeat parameter details. It reinforces that zpid refers to a home, but adds no new parameter-level semantics beyond the schema.

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 identifies the resource: agents ranked around a home by sales, and enumerates the expected output fields. The coda 'Who actually sells here' captures the purpose in a way an agent can confidently distinguish from listing-agent or property lookups.

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 'around a home' and 'who actually sells here' makes the intended use case clear: get the local agent landscape for a property. It does not explicitly name alternatives or exclusions, but the context is unambiguous enough to guide selection.

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