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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety and external-source profile is covered. The description adds genuinely new context by promising each fact carries its federal source and date, which tells the agent the output is citable. It omits behavior that matters for this kind of aggregation: latency across many federal lookups, and what is returned when a given dataset has no coverage for an address.

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?

A single sentence that front-loads the usage trigger before the enumeration, which is the right ordering for tool selection. The long fact list is functional rather than padded, since it is what distinguishes this tool from its siblings, though it could be trimmed or grouped without losing routing signal.

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 has three optional parameters, zero required, and no output schema, which leaves a real ambiguity the description does not resolve: whether to pass address, lat/lon, or both, and what happens if neither is supplied. It is otherwise complete enough for a read-only lookup, since annotations cover safety and the description covers data domains and sourcing.

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 lat, lon and address, and the description adds no syntax, precedence or formatting guidance for any of them. It reinforces the address-centric framing via "any US address" but never explains the address-vs-coordinates choice. Baseline 3 applies where the schema does the heavy lifting.

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 names a concrete resource (area facts around a US address) and enumerates the specific data domains it returns — school district, Opportunity Zone, radon, FEMA risk, flood claims, walkability, broadband, etc. That is far more than a restatement of the name and lets an agent recognize the tool. It stops short of explicitly differentiating itself from siblings like get_listing_facts or get_parcel, which it partly overlaps with.

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?

"Use this when someone asks about the area around any US address, in any state" is an explicit positive trigger, and "in any state" clarifies nationwide scope. However, it gives no exclusions or alternatives: it never says when to prefer get_parcel or search_lots, nor when this should be skipped because a more targeted sibling is cheaper.

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