Institution Portfolio (13F)

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

With readOnlyHint=true already covering the safety profile, the description adds genuinely useful behavior: values use report-date closing prices, may fall back to filer values, can be zero when unavailable, and coverage is limited to tracked U.S.-listed common stocks plus related put/call positions. It stops short of describing pagination behavior or result ordering beyond 'largest positions by published value'.

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?

Four tightly packed sentences, front-loaded with purpose before the data caveats. Every sentence carries information, though the parenthetical about default/max rows is redundant with the schema and could be dropped.

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, so the description usefully enumerates the returned fields and flags data-quality edge cases (zero values, options ambiguity, coverage limits). The one remaining gap is what happens for an institution with no 13F-HR filings or an out-of-range offset, but the definition is otherwise call-ready.

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 the schema already documents all four parameters, including clamping ranges, date snapping, and pagination math. The description only restates the default/max row count (20 / 500), adding essentially nothing beyond the schema — the baseline 3 for full coverage is appropriate.

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 precise verb and resource: view tracked stock positions of a specific institutional investor from an SEC 13F-HR filing. It also names the fields returned (share counts, value, percent of tracked 13F value, position count), which cleanly separates it from siblings like GetTopHolders or GetMostHeldStocks that aggregate across institutions.

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?

It gives explicit routing advice ('Use SearchInstitutions first when the name is ambiguous') and a caveat for interpreting options data. However, it never distinguishes this tool from close siblings such as CompareInstitutionPortfolios, GetInstitutionSummary, or GetInstitutionalOwnershipHistory, so the agent must infer when this single-holder snapshot is preferred.

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