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

Annotations already cover readOnly, idempotent, and destructive hints, so the safety profile is handled. The description adds value beyond annotations by disclosing that no auth is required, that the source is US Gov public domain, and by enumerating the return fields (enforcement activity type, settlement date, penalties, SEP amounts). It also reveals the dependency on a prior facility_search call.

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?

Four sentences, each carrying distinct information: the core action, return fields, ID source, and use-case/source/auth context. It is front-loaded with the purpose statement and avoids redundancy, though the 'Critical for...' clause is slightly promotional.

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 an output schema and annotations, the description is complete: it covers purpose, prerequisite, return content, source, and auth. Nothing an agent needs to call it correctly is missing.

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%: registry_id has a description with an example and source. The tool description reinforces the source (facility_search) but adds no new format, syntax, or behavior details beyond what the schema already provides, so a baseline of 3 is appropriate.

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 ('Retrieve') and resource ('enforcement actions and violation history for a specific EPA-regulated facility'), making the tool's purpose immediately clear. It distinguishes itself from siblings by naming the ID source (echo.compliance.facility_search) and listing unique data fields such as penalties, SEP amounts, and program codes.

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?

It explicitly tells the agent that Registry IDs come from echo.compliance.facility_search results, establishing a prerequisite and routing the agent to the correct sibling tool. It also names concrete use cases (environmental liability, ESG due diligence, compliance monitoring), which help an agent decide when to invoke it. It does not name exclusions versus facility_detail, but the guidance is sufficient.

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