Top Institutional Buyers and Sellers

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

With readOnlyHint=true already covering the safety profile, the description layers on genuinely useful behavior: new/sold-out position treatment (Δ = full position / −prior position), the requirement of observed filings in both quarters, CIK-successor handling, an explicit note that open filing windows yield partial results, and disclosure that excluded filers/shares are counted and the largest named. This is far beyond what the annotation conveys.

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?

Purpose and comparison window are front-loaded, and most clauses earn their place by encoding real edge-case rules. The dense semicolon-chained middle is heavy to parse, and the closing sentence is pure sales copy that adds no selection value.

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?

No output schema exists, and the description compensates by stating the return shape ('a markdown table with two sections') plus the caveat that open filing windows produce partial coverage. Combined with the exclusion/counting rules, an agent has everything needed to call and interpret this tool.

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 ticker, maxResults, and reportDate are already fully documented with defaults, clamps, and snapping behavior. The description adds nothing parameter-specific beyond restating 'this quarter' (matching reportDate's latest-available default), so baseline 3 applies.

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 names a precise verb+resource and defines the exact metric: biggest absolute share additions (Top Buyers) and reductions (Top Sellers) versus the previous 13F report date. This quarter-over-quarter change framing clearly separates it from siblings like GetTopHolders and GetInstitutionalOwnershipHistory, which describe static or historical ownership rather than the buyer/seller delta.

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?

Only one usage statement is given — 'Use this to surface the most actionable quarterly signal from 13F filings' — which is promotional rather than directive. It never names an alternative (e.g., GetTopHolders, GetMarketWide13FActivity, GetInstitutionQuarterlyActivity) or states when not to use it, so the routing burden falls on the agent inferring scope from the definition alone.

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