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

With no annotations at all, the description has to carry the full behavioral load, and it does disclose the most consequential non-obvious trait: the metered payment model, the price ($0.002 USDC on Base), and that failed/nonexistent reads cancel settlement. That is real value beyond the schema. It stops short of saying anything about rate limits, latency, or whether invalid-input cancellation is automatic or requires a signature.

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 what the tool returns, then a compact billing caveat, then the price. The long field enumeration is not padding — it substitutes for the absent output schema — so every clause carries information.

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?

Full parameter coverage, no output schema, and no annotations, so the description correctly fills the return-shape gap by listing the payload fields, and it covers the payment model. Remaining gaps are minor: error behavior beyond 'settlement is cancelled' and any freshness/caching characteristics of the SEC data are not stated.

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 cik, ticker, and paymentSignature are already documented in structured form. The description adds marginal meaning — that payment is only settled on success, which contextualizes paymentSignature — but gives no syntax or format detail beyond the schema. A baseline 3 fits.

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 a specific resource (official SEC profile of a US public company) and enumerates exactly which fields come back — legal name, tickers, exchanges, SIC, incorporation state, fiscal year end, website, address, former names, report links. That enumeration makes it clearly distinct from siblings such as company_filings, company_financials, and company_insider_trades.

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: the schema says 'Provide ticker or cik', so an agent can infer this is the entry point for looking up a company from either identifier. But there is no explicit guidance on when to call company_profile versus company_search or company_filings, and no statement of prerequisites or exclusions.

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