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

Annotations already cover the read-only/idempotent profile, and the description adds materially new behavior: a tiered cost model (5 credits full success, 3 on partial federal failure, 0 on unresolvable point), failure semantics, an explicit exclusion ('never owner data'), a Colorado attribution obligation, and three scope disclaimers. These are exactly the operational facts an agent cannot infer from the 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?

A single front-loaded block that leads with what the screen returns before costs and disclaimers. Dense but nearly every clause carries operational value; only the parcel-field enumeration is slightly over-detailed relative to the rest.

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 and no required parameters, the description does the work of describing return sections, cost outcomes, and legal caveats. The remaining gap is the unaddressed zip/city parameters and the absence of any hint about response shape beyond the section list.

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 0% across 8 parameters, so the description must carry the load. It explains epa_radius_mi (default 1, max 3) and three valid location combinations, but leaves zip and city entirely undocumented and gives no format hints for lat/lon or state codes.

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?

States a specific verb+resource ('Site screen for one location') and then enumerates exactly what the screen returns: parcel facts, FEMA flood zone, EPA-regulated sites, USFWS wetlands, and Census tract. The enumeration of parcel fields versus federal layers makes it clearly distinct from a parcel-only sibling like query_parcels.

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?

Gives concrete locating modes ('lat+lon, address+state, or parcel_id+state') and a fallback rule ('Federal layers are returned even where no parcel is available'), which tells the agent when the tool still succeeds. It does not explicitly route against siblings such as query_parcels or mortgage_precheck, so it stops short of full alternative guidance.

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