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

Beyond the readOnlyHint, idempotentHint, and destructiveHint annotations, the description adds meaningful behavioral context: data comes from public SEC filings, is read automatically, may contain errors, and should be presented with source links and without investment-advice framing. This substantially helps the agent set user expectations and handle results correctly.

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 a single dense sentence that front-loads the core capability and then appends the necessary data-source, accuracy, and usage caveats. Every clause earns its place, with no filler or redundant restatement.

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?

For a one-parameter read-only tool, the description covers the query semantics, the result content (funds, share, report date, as-of dates, source links), and important reliability caveats. It does not specify the exact response shape or no-results behavior, but the absence of an output schema makes the provided field-level detail sufficient for safe invocation.

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 single required parameter 'query' is already fully documented in the schema with accepted forms and an example. The tool description rephrases that a company/bond name, CUSIP, or ISIN can be used but does not add new parameter-specific meaning beyond what the schema provides.

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 states a specific verb and resource: it lists U.S. closed-end funds from SEC filings based on a named security, CUSIP, or ISIN, and includes each fund's share and report date. This clearly differentiates it from siblings like get_fund_holdings, which would look up holdings for a given fund rather than funds holding a given security.

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 implies the tool should be used when you need to find which funds hold a particular security, and the schema reinforces the accepted query forms. However, it does not explicitly state when not to use it or name sibling alternatives for the opposite lookup direction, so the usage guidance is mostly inferred.

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