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

The description discloses what the tool returns (zone code, insurance requirement, base flood elevation, annual probability) and notes it uses the official FEMA API. This adds behavioral context beyond the annotations (readOnly, idempotent), which already indicate a safe read operation. It doesn't cover edge cases or errors, but given the strong annotation coverage, this is adequate.

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?

The description is well-structured and front-loaded with the core purpose, followed by concise 'USE WHEN' and 'RETURNS' sections. Every sentence conveys necessary information (purpose, usage triggers, output details, data source) without redundancy, making it highly efficient.

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?

The tool is simple (one parameter, no output schema), and the description covers the essential aspects: what it does, when to use it, and what it returns. It does not describe error handling or invalid address behavior, but for a low-complexity lookup tool with strong annotations, this is sufficiently complete.

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 already provides 100% coverage for the single parameter 'address' with a clear description ('Full U.S. property address'). The tool description adds context about U.S.-only usage and the FEMA API but does not add further parameter-level details like format examples or constraints, so the value added is minimal 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 states the tool's function: 'Check FEMA National Flood Hazard Layer for any U.S. property.' It is specific about the verb (check), resource (FEMA NFHL), and scope (any U.S. property), and it distinguishes itself from siblings like check_environmental_risks by focusing exclusively on flood zone data.

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 description provides explicit 'USE WHEN' triggers with example user queries ('is this in a flood zone', 'do I need flood insurance', 'FEMA flood map'), giving clear guidance on when to invoke this tool. However, it does not explicitly mention when not to use it or alternative tools, so it falls short of a 5.

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