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

With no annotations, the description usefully discloses a $0.05 USDC charge, the EDGAR source and fair-use constraint, and the approximate 15-filing scope. It does not discuss failures, freshness, or explicitly state read-only behavior, but this is useful additional context for a simple snapshot lookup.

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 leading sentence efficiently combines purpose, inputs, and outputs, while the example and prices are compact. "Upsell us_sec_full" and the following "Related" sentence duplicate the sibling referral, so not every phrase earns its place.

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 lookup without an output schema, the field list, filing-limit approximation, cost, and full-version alternative cover most selection and invocation needs. The main remaining gaps are identifier validation and precedence, plus operational details such as freshness or not-found behavior.

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 descriptions are absent, and the description partially compensates by saying lookup is "by ticker or CIK" and showing {ticker:"AAPL"}. It does not define CIK formatting, whether exactly one identifier should be supplied, or precedence when both are present, despite neither parameter being required.

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?

It identifies a US SEC EDGAR company snapshot, the ticker/CIK lookup modes, and concrete contents such as SIC, EIN, addresses, and roughly 15 recent filings. It also distinguishes the fuller sibling by describing us_sec_full as providing full financials and a filings list.

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?

"Use this for a cheap" snapshot establishes when this lightweight option is appropriate, while the $0.25 us_sec_full pointer routes full-financials and filings-list needs elsewhere. Although "Upsell" is marketing-oriented, the alternative and price distinction remain actionable.

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