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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower, and the description adds real context: it clarifies this is metadata-only and does NOT fetch or inspect the geodatabase, plus mentions 'immutable provenance' in the return. It stops short of stating rate limits or error behavior.

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?

Three tight sentences: identity, return fields, then usage/routing. The alternative is placed last as a redirect, and nothing is padded or repeated.

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 compensates by enumerating the returned fields (jurisdiction, state, coverage-unit kind, update date, size, filename, URL, provenance), which is genuinely helpful. Combined with the boundary statements it is nearly complete, though it omits any note on missing/invalid DFIRM ID behavior.

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 100%, so both parameters are already documented in the schema; baseline is 3. The description only reinforces 'exact DFIRM ID' and adds no format or suffix guidance beyond what the schema provides.

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+scope: fetch one inventory unit by exact DFIRM ID. It distinguishes itself from fema_nfhl_search_inventory ('after search'), fema_nfhl_compare_inventory_items, and flood_zone_lookup, 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?

Explicit when-to-use ('produce acquisition evidence after search') and an explicit when-not/alternative ('does not fetch or inspect the geodatabase; use flood_zone_lookup for address/coordinate zone questions'). Both the trigger and the handoff are stated, not inferred.

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