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

Annotations declare read-only/idempotent/non-destructive, and the description adds the crucial commercial behavior: paid at $0.01 USDC per successful call via x402 on eip155:8453, not charged on failure or not-found. That is exactly the extra context the annotations cannot express, and it is stated plainly.

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?

One dense sentence covering output, then short sentences for scope, failure policy and pricing. It front-loads the purpose. It is somewhat list-heavy in the first sentence but no clause is purely wasted.

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 lookup with no output schema, the description fully prepares the agent: input types, returned sections, company-only scope, billing model, and non-charge-on-failure behavior. Nothing an agent needs to decide or invoke safely 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 restates that ticker or CIK is accepted and implicitly references the filings/forms filter ('recent filings', '8-K item titles'), but it adds no format or default details beyond the schema's own parameter descriptions.

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 ('returns') and resource ('EDGAR profile') and enumerates exactly what the payload contains: profile fields, XBRL annual financials, and recent filings with 8-K items. 'Companies only' clarifies scope and separates it from sibling tools like company_card or recalls.

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 clear trigger conditions: 'Given a U.S.-listed company's stock ticker or SEC CIK' and 'Companies only.' It does not name alternatives such as company_card or scrape_business, so there is no explicit when-to-use-instead-of routing, but the required input type is unambiguous.

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