echo_facility_report

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

Annotations already declare readOnlyHint=true, and the description adds valuable context: 'never a fabricated report', output structure including _meta, and error behavior on bad RegistryID. No contradictions.

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?

Three sentences, each with a clear role: purpose, input, output/behavior. No unnecessary words, front-loaded with the most critical information.

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 read-only tool, the description covers purpose, input, output format, error behavior, and usage scenario. No missing elements given the simplicity.

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% with a detailed description of registryId. The tool description adds context about source (echo_search_facilities rows), validation (all-digit, 9–12 digits), and error behavior, going beyond 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?

The description explicitly states 'Fetch the EPA ECHO Detailed Facility Report (DFR) for ONE facility by its FRS RegistryID', providing a specific verb, resource, and scope. It distinguishes from the sibling tool echo_search_facilities which is for searching facilities. No ambiguity.

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 explains when to use: 'for competitor or acquisition-target due diligence', and clarifies input source: 'from echo_search_facilities rows'. It also describes behavior on bad input but does not explicitly state when not to use, though the unique purpose makes it clear.

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