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

Annotations already indicate readOnly, idempotent, open-world, and non-destructive behavior. The description adds meaningful detail beyond those annotations, including the best-effort nature of the parse, the HTML source, and specific conditions leading to an empty result (companies listing only significant subsidiaries or omitting Exhibit 21).

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 two concise, information-dense sentences. The primary output and source are front-loaded, followed by necessary caveats, with no redundant or ambiguous phrasing.

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?

Although the tool has only one parameter and useful annotations, it lacks an output schema, and the description does not specify the exact result shape (e.g., array of objects with 'name' and 'jurisdiction' fields). This could leave an agent uncertain about how to consume the response, so completeness is only moderate.

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?

The only parameter, 'ticker', is fully documented in the schema as 'US stock ticker or CIK, e.g. AAPL'. Since schema coverage is 100%, the description adds no additional parameter-level meaning, warranting the baseline score of 3.

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 clearly states what the tool returns: the company's subsidiaries and their jurisdictions of incorporation, parsed from Exhibit 21 of the latest 10-K. Reference to Exhibit 21 and the specific data type makes it distinguishable from sibling tools like get_company or get_sections.

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: data comes from the latest 10-K's Exhibit 21, with important caveats (best-effort parsing and empty results for certain filers). It does not name alternative tools, so it lacks full when-to-use versus when-not-to-use guidance, but the intended scenario is apparent.

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