Institutional Ownership History

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

With readOnlyHint=true already covering safety, the description adds substantial behavioral context: the legacy Total Shares field is not a pure share-ownership measure, QoQ change is like-for-like with exclusions noted, missing filings are not treated as trades, values use report-date closing prices with possible fallbacks and zeros, and the newest quarter uses a provisional combined view for non-ETF primary stocks while ETFs remain exact.

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 purpose is front-loaded in the first sentence, and the dense caveats that follow are relevant and earn their place. The description is long and clause-heavy, but the complexity of the 13F data aggregation justifies most of the detail.

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?

There is no output schema, but the description explains the key returned fields (total reported quantity, published position value, filer count, QoQ share change with exclusions) and the important caveats about provisional data and fallback values. An agent has enough information to call and interpret the tool correctly.

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 both the ticker and maxPeriods parameters are already documented in the schema. The description reinforces that ticker should be an exact stock or ETF listing and mentions multiple quarters, but it adds little syntax or format detail 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: get the historical trend of aggregate reported 13F exposure for an exact stock or ETF listing across multiple quarters. It also names the metrics returned (quantity, position value, filer count), making the tool clearly distinguishable from siblings like GetTopHolders or GetHolderMix.

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 usage through phrases like 'exact stock or ETF listing' and 'across multiple quarters,' but it does not explicitly say when to use this tool versus alternatives such as GetInstitutionQuarterlyActivity or GetTopInstitutionalBuyersSellers. The detailed caveats are helpful but are not usage routing guidance.

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