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

Annotations already mark readOnlyHint=true and destructiveHint=false. The description adds valuable behavioral context: N-CEN is filed at registrant level, ingestion happens through tracked issuer feeds, and a series in an untracked multi-series trust may have no record. It also clarifies the 'operating companies return no data' boundary. No contradiction with annotations, and it enriches beyond the structured hints.

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, well-structured paragraph. It leads with the purpose, then details accepted inputs, the data returned, and important caveats about data availability and filing scope. Every sentence adds value without redundancy. It is appropriately sized for the tool's complexity.

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 read-only tool with two parameters and no output schema, the description covers the essential usage context: accepted identifiers, report contents, data availability limitations, and filing eligibility. It does not explicitly describe the return format (e.g., list vs. single record) or pagination behavior for maxResults, but maxResults is self-explanatory and the listed fields imply a structured response. Minor gaps exist but are not critical.

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 input schema covers 100% of parameters with descriptions and examples. The description adds meaning by specifying that identifiers come from SearchFunds and detailing the accepted identifier types (profile id, SEC series id, stored series ticker, verified share-class alias). This goes slightly beyond the schema's generic 'Fund or ETF ticker' and clarifies the data source relationship.

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: 'Get operational data for a registered investment company from its SEC Form N-CEN annual reports.' It clearly distinguishes from sibling tools like GetFundProfile by focusing on N-CEN filings, and it enumerates the data fields returned. No ambiguity or tautology.

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 gives clear context: it accepts tickers or identifiers from SearchFunds, and notes that only registered funds file N-CEN, with operating companies returning no data. It implies when to use this tool, but does not explicitly name alternative tools or state when not to use it. The guidance is solid but not exhaustive.

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