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

Annotations already mark this as read-only and non-destructive, and the description goes well beyond them: it warns that non-derivative and derivative totals use different units and must not be added, that filing counts include filings with no holdings, that _warnings must be read before using totals, that out-of-coverage tickers return 403 and are still charged, and it states credit costs. This is rich behavioral disclosure.

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 description is dense and front-loaded with the core purpose and metric list. It is long, but nearly every clause earns its place given the tool's complexity; minor extras like the POST path and documentation filename are slight overhead rather than significant bloat.

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?

Given 11 parameters, no output schema, and no enums, the description is unusually complete: it names the returned aggregate fields, explains unit incompatibility, warns about anomaly/amendment behavior, identifies the provenance mechanism, and discloses error and pricing behavior. An agent has enough context to invoke the tool and interpret results correctly.

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; the description adds value by explaining that the date fields define a filing-date window, that ticker out-of-coverage has a charge implication, and that holding_ids are paged and fetched with a sibling tool. This is meaningful enrichment beyond the schema, though not exhaustive for every parameter.

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 opens with a specific verb and resource: it aggregates over Form 3 filings in a filing-date window and enumerates the exact computed metrics. It also distinguishes itself from the row-level sibling by noting that holding_ids should be fetched with get_initial_holdings_by_id, so an agent can tell aggregate from detail tools.

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 provides clear context: use this tool for aggregate Form 3 statistics within a filing-date window, and use get_initial_holdings_by_id to fetch the underlying holding rows referenced by holding_ids. It does not explicitly enumerate when not to use related list/search tools, but the aggregate-vs-row distinction is strong enough to guide selection.

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