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

Annotations already cover read-only/idempotent/non-destructive, but the description adds substantive context beyond them: the 28-credit cost is debited even on missing filings, non-SEC filings, or absent statements; a 404 is returned when no equity statement exists; and light_weight_mode drops verbose nested fields at the same price. These are the operational facts an agent needs before calling.

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 the return value, then identification, then sibling routing, then constraints and cost. It is dense but every sentence carries distinct information (shortcut equivalence, credit policy, SEC-only scope, endpoint reference) and none is redundant with the schema or annotations.

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?

With no output schema, the description still characterizes the return ('extracted line items with values and periods') and covers cost, error behavior, jurisdiction limits, and the lightweight option. Nothing an agent needs to call this correctly 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 description coverage is 100%, so the baseline is 3 and the schema already documents each field. The description adds value by clarifying the identification logic (filing_id OR ticker + fiscal_year, quarter optional to disambiguate), the absence of role_label/statement_type, and the trade-off behind light_weight_mode ('saves context when you already know exactly what you need').

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 verb and resource ('Return the filing's Statement of Stockholders' (or Shareholders') Equity') plus the shape of the payload (extracted line items with values and periods). It explicitly distinguishes itself from get_filing_statement by framing itself as 'a fixed shortcut for get_filing_statement(statement_type='Stockholders Equity')' and notes it does not take role_label/statement_type.

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 concrete filing-identification paths (filing_id, or ticker + fiscal_year with optional quarter) and names the alternative (get_filing_statement) with the reason to prefer this shortcut. It also states the exclusion conditions: SEC-only availability, 404 when no equity statement exists.

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