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

Annotations already declare this as a read-only, idempotent, non-destructive operation. The description adds useful detail about what the report contains, which goes slightly beyond the annotations. It does not disclose potential edge cases, data availability caveats, or whether the report may omit facilities with no compliance history, but for a read-only report the description is adequate.

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?

Two tight sentences: the first states the core purpose and output detail; the second gives the only prerequisite. No filler, no repetition of schema metadata, and the most important facts are front-loaded.

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 read-only tool, the description provides adequate context: it names the covered statutes, the kind of compliance data returned, and the required input. There is no output schema, so describing the returned metrics was necessary and done well. A small gap is the lack of any note about handling facilities with no recent inspections or non-compliance records.

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?

There is only one parameter, registry_id, and the schema description fully documents it, including type, source tool, and an example. The description's mention of 'Requires an EPA Registry ID' adds no semantic detail beyond the schema. At 100% schema coverage, the baseline of 3 applies.

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 clear verb and resource: it reports a facility's current compliance status and recent non-compliance history by environmental program. It also lists specific outputs ('quarters in non-compliance', 'last inspection per statute'), making the tool's function concrete. It does not explicitly distinguish itself from epa_facility_details or epa_enforcement_search, so it falls just 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 implies when to use the tool: when you have an EPA Registry ID and need compliance status/history for a facility. It explicitly states the prerequisite ('Requires an EPA Registry ID'), which is useful. However, it provides no guidance on when not to use it or which sibling tools to prefer, such as epa_enforcement_search for enforcement records or epa_facility_details for general facility information.

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