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

Goes well beyond the readOnly/idempotent annotations: it defines the `standing` semantics ('clear only when every list was checked and found nothing'), discloses that SAM.gov and domain reputation checks are conditional ('when keyed', 'when the operator enabled them'), and warns that a name match is not an identity match. That conditional-coverage disclosure is exactly the kind of caveat annotations cannot express. It does not mention rate limits or latency on the multiple external lookups.

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-loads the purpose and the required input correctly, but the enumeration of every provider (OFAC SDN/consolidated, GLEIF, EDGAR, OpenCorporates, SAM.gov, RDAP, Spamhaus/URIBL/SURBL/Safe Browsing) makes the middle a dense run-on clause that is harder to scan than it needs to be for tool selection purposes.

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-shape burden and does so: it names `standing`, `findings`, and the per-section results for each source, plus the caveat on what 'clear' guarantees. Combined with the conditional-source notes, an agent has enough to decide, call, and interpret the tool.

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%, so baseline is 3, but the description adds real semantics: `name` is the anchor parameter while `domain`, `state`, `number` and `ein` are optional corroborators, and it clarifies `state` is two letters. This resolves the ambiguity created by the schema declaring zero required parameters, telling the agent what to supply minimally.

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?

Opens with a concrete question-resource framing ('Is a business on anybody's list?') and then names the specific result field (`standing`) plus every data source consulted, so the agent knows this is a business due-diligence/aggregate-risk lookup. It does not explicitly contrast itself with the adjacent `check_domain` or `reputation_lookup` siblings, which is the only thing keeping it off 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?

Usage is implied by 'Give its `name`, and any of `domain`, `state`...' – the agent can infer it needs at least a name. The closing caveat 'A name match is not an identity: confirm against address and identifiers' gives useful interpretation guidance, but there is no explicit when-to-use/when-not or pointer to the alternative tools (check_domain, reputation_lookup) that overlap on domain/risk checks.

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