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

The annotations already declare readOnly/idempotent/non-destructive/openWorld, and the description adds genuinely new behavior: a concrete price ('$0.0100 production USDC via x402 on Base mainnet'), the fact that resolving an unknown CIK costs a separate paid call, what the response contains (forms, dates, accession numbers, document URLs), and the caveat that forms must be inspected for 10-K/10-Q. None of that is recoverable from the structured fields.

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 the cik prerequisite are front-loaded, and each clause carries information (scope, prerequisites, cost, return contents, exclusions). The result is dense and slightly overloaded for one block, but no sentence is 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 two-parameter, paid, read-only lookup with an output schema and full annotation coverage, the description supplies everything else an agent needs: preconditions, cost, response shape, limitations, and an invocation example. Return values are explicitly described even though an output schema exists, so there is no ambiguity about what comes back.

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 0%, so the description must carry parameter meaning; it partially does by explaining where cik comes from and supplying example arguments {"cik":"0000320193","limit":5}. The limit parameter is only demonstrated numerically and never explained as a result count, and the cik format (digits only) is left entirely to the schema pattern.

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 verb and resource ('Find recent SEC EDGAR filing records') and enumerates use cases (financial research, issuer due diligence, regulatory-event checks). It does not, however, differentiate itself from the very similar sibling tools get_company_filings and get_entity_filings, which an agent could easily confuse with this one.

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 an explicit prerequisite workflow: 'Requires cik; if unknown, first use search_sec_company by name/ticker', and flags that the lookup is a separate paid call, which is exactly the kind of when-to-use routing an agent needs. It also states clear exclusions ('No form filter, complete documents, financial extraction or investment advice'), though it never says when to prefer get_company_filings or get_entity_filings instead.

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