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

Adds real context beyond the readOnly/destructive annotations: the data source (EPA ECHO Exporter monthly snapshot) and an important freshness caveat that state reporting schedules cause recent enforcement to lag. What's missing is any note on return shape or size limits, though the lack of pagination parameters makes that a minor gap.

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?

Front-loaded with the verb and scope, then the output contents, then the data-freshness caveat, then the disambiguation sentence. Every sentence carries distinct information with no repetition of schema or annotation fields.

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?

For a single-parameter aggregate tool with no output schema, the description fully covers what the call returns and its data provenance/lag characteristics. An agent has everything needed to decide to call it and to interpret the results.

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 state code format is already documented; the description nonetheless adds that the parameter selects a "whole US state or territory," clarifying granularity versus the county-level sibling. That scope distinction is the meaningful extra the schema cannot convey.

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?

Specific verb ("Summarize") plus a precisely scoped resource ("EPA-regulated facilities for a whole US state or territory"), followed by an enumeration of exactly what is aggregated: facility/county counts, inspections, formal enforcement actions, penalties, violation counts, and top violating counties. This is clearly separable from the sibling county-level and facility-level tools.

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 the agent to alternatives with conditions: "Use get_county_compliance_summary instead for one county, and list_facilities_with_violations for the facility-level worst-first list." Both the granularity boundary and the alternative tool names are stated, leaving nothing to inference.

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