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

Annotations already declare readOnlyHint and openWorldHint, and the description adds genuinely new context: the three upstream sources (Census geocoder, FEMA NFHL, NOAA) and the pricing model ($0.01 USDC via x402, charged only on success). Cost-and-billing behavior is the kind of detail an agent needs before calling and is not derivable from annotations or schema.

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, no filler: the first front-loads what the tool returns, the second covers sources and price. Every clause carries 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 must convey return content, and it names the flood zone/SFHA determination and active alerts plus the underlying sources. It stops short of describing output shape (e.g., whether alerts are a list, how zones are keyed) and geocoding failure behavior, but it is sufficient to call 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?

Only one parameter with 100% schema coverage including a concrete example address, so the schema does the heavy lifting and the baseline is 4. The description reinforces the constraint ('US street address') but adds no format or parsing detail beyond the schema example.

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 ('Hazard snapshot for a US street address') and enumerates the exact contents: FEMA flood zone, Special Flood Hazard Area flag, and active NWS alerts. That is far more specific than any sibling (recalls, VIN, SEC filings, contractor lookup), so an agent can route to it 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?

The scope constraint 'US street address' is stated and implies applicability, but there is no explicit when-to-use guidance, no mention of non-US addresses being unsupported as an exclusion, and no comparison to sibling tools. Usage is inferable from the subject matter rather than prescribed.

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