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

Annotations already declare readOnly, idempotent, non-destructive, openWorld, so the safety profile is covered. The description adds non-obvious behavioral context the annotations cannot: the data source (SEC EDGAR XBRL), the pricing model ($0.03 per successful call, failed calls free), and that results carry latest annual and quarterly values with period/form/filing date.

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 the resource and return fields, then source and pricing. Dense but every clause carries information; the SEC non-affiliation disclaimer is the only mildly expendable element.

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?

An output schema exists, so return-shape explanation is unnecessary. The description covers source, cost, default metrics, and value granularity (annual + quarterly with period/form/filing date), leaving only minor gaps such as error/empty-result 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 description coverage is 100%, so both ticker_or_cik and metrics are already documented in the schema, including the default metric set and the Revenues fallback concepts. The description restates the metric examples but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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 specific resource (key financial numbers for a US public company) and the keying method (ticker or CIK), then enumerates the concrete metrics returned. An agent can clearly separate this from company_filings or insider_trades without opening a schema.

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?

The description implies when the tool fits (getting financial statement values) but never names an alternative or an exclusion condition relative to siblings like company_filings or insider_trades. The default metric list and the 'or any XBRL concept you name' note give context but not routing guidance.

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