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

The annotations already establish a safe read, but the description adds substantial behavior the annotations cannot: a flat 3-credit charge regardless of result size, no charge for uncovered counties or failures, and paging via offset being separately billed. Auth requirements and the meaning of the returned record fields are also disclosed.

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?

Six short sentences, all front-loaded: purpose first, then cost, limits, auth, charge exceptions, and return payload. Nothing is repeated and no sentence could be dropped without losing information an agent needs.

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 takes on the burden of describing returns and does so concretely (WKT boundaries in EPSG:4326, owner, address, assessed values, land use, zoning, with a caveat that zoning is county-dependent). Combined with cost, rate, and auth facts, an agent has everything needed to call it correctly and interpret the response.

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%, so the baseline is 3, and the description earns a step above it by adding the 25 km² bounding-box ceiling and the 1,000-parcel cap, neither of which is in the schema. It stops short of the 5 because the WKT coordinate order and format are already fully documented in 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 gives a specific verb and resource ("finds every parcel that intersects") and broadens the accepted input beyond the tool name by naming polygon, multipolygon, line and point WKT geometries. An agent can distinguish this from find_parcels_at_point or find_parcels_by_apn immediately, because the spatial-intersection semantics are stated outright.

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 conveys clear usage context through hard constraints: a bounding-box ceiling of 25 km², a 1,000-parcel cap, and a required API key, which tells the agent when this tool is viable. It does not explicitly route to the sibling alternatives (point, radius, APN) or state when not to use this tool, which keeps it below a 5.

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