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

Annotations already declare readOnlyHint/idempotentHint. The description adds valuable behavioral detail: it operates across loaded 13F quarters, returns position value and holder counts per quarter, and narrows mover lists to the two most recent quarters. This goes beyond annotation coverage, though it does not discuss data freshness or omissions.

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?

Every part earns its place: core function, output contents, input format, and example use cases are packed into a dense but readable description. The most important behavior is front-loaded and examples are concrete.

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 takes on the job of describing return values, and it does so well: per-quarter totals, holder counts, and the exact mover buckets. It does not specify ordering or pagination behavior, but for a two-parameter read-only tool, it is largely complete.

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 coverage is 100%: both security and limit have full descriptions in the schema. The description only repeats that the input can be a company name, ticker, or CUSIP, adding no new meaning 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?

States precisely what the tool does: computes net institutional buying/selling for a single security across 13F quarters with per-quarter totals and manager mover lists. The security-centric scope is clearly differentiated from manager-centric siblings like manager_changes and manager_portfolio.

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?

Gives two explicit, real-world example prompts that should use this tool ('is institutional ownership of NVDA growing', 'who has been buying/selling Tesla'). It does not name alternative tools or exclusion conditions, but the user queries provide clear when-to-use guidance.

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