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

Annotations already declare the operation as read-only, idempotent, and non-destructive, covering the safety profile. The description adds useful behavioral context by specifying that output is organized by environmental program and includes quarters in non-compliance, significant non-compliance, and last inspection per statute. It does not discuss data freshness, error handling, or response format, but these are secondary given the annotation coverage.

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?

The description is two sentences long with all information front-loaded: purpose first, then output specifics, then the prerequisite. There is no filler or vague language. The only minor redundancy is restating the registry ID requirement, but it is useful as an invocation prerequisite.

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 one-parameter tool with no output schema, the description is nearly complete: it explains what is reported, the scope by statute, the specific output fields, and the required input. It does not explain how to obtain the registry ID, but that is covered in the schema parameter description, or how errors are surfaced, which is a minor gap.

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%, and the single parameter registry_id is well documented with type, format, example, and its source via epa_facility_search. The description simply restates that a Registry ID is required, which adds no new semantic information. The baseline of 3 is appropriate because 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 states a specific verb and resource: it reports a facility's current compliance status and recent non-compliance history by environmental program. It also lists the specific statutes and output fields, making the tool's function clear. However, it does not explicitly differentiate itself from sibling EPA tools like epa_facility_details or epa_enforcement_search, so it stops short of a 5.

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 description provides a key prerequisite: 'Requires an EPA Registry ID.' This implies the tool should be used after obtaining an ID, and the schema parameter description points to epa_facility_search as the source. It does not explicitly state when to prefer this tool over related EPA tools or when not to use it, so usage guidance is present but implicit.

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