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

Annotations already cover safety (readOnlyHint, idempotentHint, openWorldHint), but the description adds substantial context beyond them: the underlying sources (GLEIF LEI index, US SEC EDGAR), the four-way verdict vocabulary, the conservative near-match behavior ('a near name match is never reported as a match'), and an Ed25519-signed receipt verifiable offline against a published key. That is exactly the kind of audit/trust behavior an agent cannot get from the annotation block.

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?

Front-loaded with the core question, then constraints, then the receipt mechanism — a sensible ordering with no filler sentences. The receipt sentence is long and appends audit detail rather than selection-relevant guidance, so it is dense but not wasteful.

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?

With no output schema, the description carries the return-value burden and does so (four verdict values plus near-match caveat), and it names the sources and the verification artifact. It omits operational facts such as rate limits, cost, or authentication needs, but for a read-only lookup tool this is close to complete.

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%, so the baseline is 3. The description references 'under which identifier and jurisdiction' and the notion that an identifier resolves exactly, mirroring the schema (which already documents name/LEI/CIK and jurisdiction examples), but adds no new syntax or format detail beyond what the schema provides.

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?

States a specific verb and resource ('Verify a legal entity') and immediately unpacks the scope into three concrete sub-questions: existence, identifier/jurisdiction, and registration currency. Scope exclusions ('not advice, not a credit check, not a sanction screen') further sharpen what the tool is, letting an agent separate it from check_figure and verify_citation without opening a schema.

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 gives clear when-not guidance ('not advice, not a credit check, not a sanction screen') and states the output space (found/ambiguous/not_found/unknown), which frames when the tool applies. It stops short of naming a sibling tool as the alternative for the excluded cases, so routing among the other verification tools is left to inference.

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