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

With no annotations, the description carries the full burden and does so: it discloses the pay-per-call price ($0.005 over x402 with specific rails), the refusal-before-payment behavior for unfound companies, and the exact sign-then-resubmit payment workflow. These are precisely the behavioral traits an agent cannot infer from the schema.

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?

The purpose and sources are front-loaded, then constraints, then payment mechanics, so an agent can stop reading early. It is information-dense but the payment sentences are long; a little tightening would help without losing content.

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 four-parameter query tool with no output schema and no annotations, the description covers the sources, the field-level contents of the response, the failure mode, the cost, and the full payment handshake. Nothing an agent needs to call it successfully 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 coverage is 100%, so the schema already documents lei, name, ticker, and payment, making 3 the baseline. The description adds genuine value by clarifying that name/lei/ticker are interchangeable entry points and by explaining the otherwise-opaque payment parameter's role in completing the purchase in-call.

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 and resource ('identity from the public registries') and names the two exact sources (GLEIF for legal name/LEI/jurisdiction/status/HQ/parents, SEC EDGAR for US filers with CIK, industry, and filing dates). This distinguishes it from adjacent siblings like domain_check, email_check, and token_lookup.

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 gives explicit input modes ('Pass name, lei or ticker') plus a clear exclusion ('Not sanctions screening or KYC'), which routes agents away from compliance-style tools. It also gives the two-step condition for payment that no other sentence could replace.

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