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

Annotations only cover the read-only and closed-world profile; the description goes further by disclosing that results include the parent control group, portfolio home count, and an institutional-investor classification under the 350+ home ROAD Act threshold. It doesn't describe null/empty behavior when an address is outside coverage, which is the main remaining behavioral gap.

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 sentences with zero filler: capability and returned fields first, then the coverage constraint. The county list is long but is load-bearing for deciding whether to call the tool at all.

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 description carries the burden of describing returns and does so adequately: owner of record, parent entity, home count, ROAD Act flag. Combined with the coverage limits, an agent has enough to call and interpret it; only the not-found case is unspecified.

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 coverage is 100% and both parameters are already documented with format hints ('5-digit ZIP', example street address), so the schema does the heavy lifting. The description adds only the US-scoping constraint on the address, which the schema does not state.

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 opens with a specific verb and resource plus required inputs: 'Given a US street address and ZIP, return the owner of record.' The home-ownership focus is clearly distinct from aircraft_owner and the organization-lookup siblings, so an agent can route without opening a schema.

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 gives a concrete applicability envelope: entity-owned single-family homes in 17 named large counties. That tells the agent when the tool will return nothing useful. It stops short of naming an alternative tool to use outside that coverage, so it lands at 4 rather than 5.

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