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

Beyond the readOnlyHint annotation, the description discloses that only filings ingested by HillSignal are included, that results are the largest holders sorted by position, and that each institution is represented by its latest position. This adds meaningful behavioral context about data scope and deduplication.

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?

Single sentence with no filler, front-loaded with the core resource, and every phrase adds scope or behavior.

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 simple read-only list tool with two well-documented parameters, the description states the source, ordering principle, and deduplication behavior. No critical invocation information appears missing.

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?

Input schema already documents both parameters at 100% coverage, so baseline is 3. The description adds context about 'largest' and 'latest position' but does not add parameter-level detail 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 identifies the resource ('largest institutional holders of a ticker') and the filing source (13F-HR), making the tool's purpose recognizable. It lacks an explicit action verb such as 'list' or 'get,' and it does not explicitly contrast with sibling tools, but the noun phrase is specific enough.

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 when to use the tool — when a user wants institutional ownership from 13F filings — but it does not provide explicit guidance or alternatives. It does not say when to prefer insider_trades, congressional_trades, or other sibling tools.

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