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

Annotations already declare readOnly, idempotent, non-destructive and open-world behaviour, so the safety profile is covered. The description adds genuine context beyond them: the jurisdictional limit (England only for permits/enforcement) and the critical caveat that a sanctions hit is a lead to confirm, never a finding. No auth, rate-limit or freshness details, but the interpretive caveat is substantive.

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?

A single dense sentence that front-loads the two main data sources before enumerating sub-checks. The parentheticals are justified by content, though the second half is packed with comma-separated clauses. No redundant filler.

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 lookup with no output schema, the description is complete enough: it tells the agent what categories of data come back and flags the England geographic limitation plus the sanctions-match caveat. Only the response shape (format/structuring of the results) is left unspecified, 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?

There is a single parameter with 100% schema description coverage ('A company number or name'), so the schema already documents it fully. The description adds nothing about accepted formats or ambiguity between number and name input, so baseline 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 the specific data sources (Environment Agency registrations, UK Sanctions List) and enumerates the returned subject matter (waste carrier/broker/dealer status, permits, exemptions, enforcement actions), which cleanly separates it from sibling register checks like cqc_check, sra_check and charity_check. It lacks an explicit action verb, but the resource and scope are unambiguous.

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?

Usage is only implied — a compliance/due-diligence lookup on a single company — with no statement of when to use this versus siblings such as public_record, company_search or aml_register. It does add one interpretive rule (the sanctions match is a lead to confirm, never a finding), which is useful but not a routing guideline.

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