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

Annotations already declare readOnly, idempotent, open-world, non-destructive, so the safety profile is covered. The description adds real value beyond that: it states what is returned (requested-order rows, missing IDs, total estimated bytes, provenance) and clarifies 'No geometry is hosted or downloaded,' which prevents misassumptions about data transfer.

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 sentences, front-loaded with the core action and scope, followed by the return summary and the routing hint. Every sentence carries distinct information; nothing is redundant with the schema.

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 steps in to describe the return payload (ordered rows, missing IDs, total bytes, provenance) and the no-geometry constraint. Combined with annotations, an agent has everything needed to call this 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?

Schema description coverage is 100%, so the schema already documents dfirm_ids and response_format. The description echoes the 2-10 exact-ID constraint and adds the word 'exact' plus the cross-county/community framing, but contributes no syntax or format detail beyond the schema. Baseline 3 is appropriate.

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 (compare), resource (FEMA NFHL inventory units), and scope (2-10 exact IDs), plus what is compared: coverage freshness and advertised download size. This clearly distinguishes it from fema_nfhl_get_inventory_item, fema_nfhl_search_inventory, and fema_nfhl_summarize_state_inventory.

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?

Explicitly routes point/address flood-zone questions to flood_zone_lookup, which is a genuine alternative. It does not, however, differentiate from its closest siblings (get_inventory_item, search_inventory), so the guidance is clear but not exhaustive.

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