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

Annotations already cover the safety profile (readOnly, idempotent, openWorld), so the bar is lower. The description earns credit by disclosing the data-source constraint — results are limited to 13F reporters, which implies quarterly, filing-lagged coverage rather than real-time ownership. It does not mention reporting lag or completeness caveats explicitly.

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?

A single front-loaded sentence with no filler; every clause (verb, resource, 13F constraint, quarter scoping) carries information.

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 should arguably say more about what a result contains (fund name, shares, value, change) and how paging works, though the cursor parameter hints at pagination. It is adequate for a simple list tool but leaves the return shape unstated.

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 ticker, quarter, limit, and cursor are all documented in the schema. The description adds no format, default, or range detail beyond that, making the baseline 3 the right call.

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?

Specific verb ('Lists') plus a precise resource ('funds that report a 13F position in a stock for a quarter'), which is the inverse of the sibling institutional_get_fund_holdings and thus reasonably distinguishable. It stops short of naming that sibling or the direction contrast explicitly, so it lands at 4 rather than 5.

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 purpose implies the natural use case (finding holders of a given ticker), but there is no explicit when-to-use/when-not guidance and no mention of the alternative institutional_get_fund_holdings for the reverse lookup. Usage is inferable but not stated.

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