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

Annotations already establish this is a non-destructive, closed-world read. The description adds genuinely extra context: county is derived from EPA/FRS coordinates using official Census county names, and the output is framed as screening-level rather than property-level. It does not discuss result limits or ranking depth for 'worst facilities,' which is the only notable omission.

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 dense paragraph with the verb and scope front-loaded, followed by the enumerated metrics and then the interpretive caveat. No filler sentences and nothing repeated from the schema or annotations.

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 takes on the burden of describing return contents and does so exhaustively, including sort order ('significant violations first') and the interpretive framing of county-level data. An agent has everything needed to call it and interpret the response.

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 coverage is 100%, so the baseline is 3. The description nonetheless adds meaning beyond the schema by explaining that county refers to the facility's physical county derived from EPA/FRS coordinates and uses official Census naming conventions, which matters for name matching. The 'state' parameter is only covered by 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?

States a specific verb and resource ('Summarize EPA-regulated facilities in one US county') and enumerates the exact metrics produced: facility counts, active counts, inspections, enforcement actions, penalties, violation counts, and worst facilities. The county scope clearly distinguishes it from get_state_compliance_summary and from per-facility tools like get_facility.

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 closing sentence establishes the intended use case — 'a screening view of an area, not a verdict on a specific property' — which implicitly routes property-level questions to get_facility. It stops short of explicitly naming the alternative sibling tools or stating prerequisites, so it is clear context without full exclusive guidance.

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