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

Beyond the readOnly/openWorld annotations, it discloses non-obvious behavior: report ownership as a range, totals are a floor when coverage.complete is false, a Schedule 13D/G holder below 5% may not have sold, and funds/insiders are already included in totals. These are exactly the interpretation caveats an agent needs to avoid wrong answers.

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 purpose is front-loaded in the first sentence and the remaining sentences carry behavioral caveats rather than filler. It is dense and long, bordering on a wall of text, but nearly every clause (coverage floor, funds counted, howToRead) 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?

With no output schema, the description fully carries the burden of explaining return values — declaredOwnership bounds, coverage, moves, insiders, funds, etfHoldings, history, heldSince, and howToRead — so an agent has everything needed to call and interpret the result.

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 schema already documents limit, moves, movesLimit, movesOffset and symbol. The description nonetheless adds value by explaining how the `moves` values behave ('sales' and other values list them in full) and by tying pagination to the previous answer's `next`, going modestly beyond the schema.

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 names a specific verb and resource ('Returns the shareholders of one company from SEC filings') and enumerates the exact holder categories and data returned, so an agent can distinguish it from get_holders, get_insider_trading and get_filings. It even notes the `holder` field is accepted by the sibling get_holders, reinforcing the boundary.

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?

It gives explicit trigger conditions ('Use it when the user asks who owns a company, who its largest shareholders are, or who bought or sold its shares') plus how to interpret and report results. It does not, however, state when to prefer a sibling tool (e.g., get_holders) instead, leaving the alternative-selection decision implicit.

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