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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing the paid-access model — $0.002 USDC per successful call via x402 on Base, Solana or Arc, with failed calls uncharged — plus the shape of the response (total hit count, latest filings with company, CIK, form, file date). Cost and payment mechanics are exactly the sort of behavior an agent must know before invoking.

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 what the tool searches, then the return shape, then the scope caveat, then the price. Four dense sentences, each carrying distinct information, with no 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 read-only, paid, open-world search tool the description covers invocation intent, output contents, a scope limitation, and payment/failure semantics. With an output schema present, return values needn't be fully specified, so nothing essential 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 baseline is 3; the description adds value by giving concrete example phrases ('climate risk', 'scope 1 emissions') that illustrate the intended query granularity and by noting results are the *latest* matches. It doesn't discuss the limit range or character constraints, but those are already in the schema.

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 concrete verb and resource — SEC EDGAR full-text search of 10-K (or other) filings whose text contains a phrase — with example queries. This clearly separates it from adjacent tools like energy_epa_flight_emissions or energy_climate_action_registry, which measure emissions rather than search filing text.

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?

Gives a clear use context (find which companies mention a phrase) and an explicit negative boundary: 'it does not extract emission numbers.' It does not name a specific sibling to use instead when actual emissions data is wanted, so it stops short of full alternative routing.

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