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

Annotations already cover the read-only, non-destructive safety profile, and the description layers on rich domain behavior: what is counted vs excluded (grants, option exercises, tax withholding, gifts, inter-insider transfers), the quarter-boundary rules and the two-business-day Form 4 deadline, data availability from Q3 2024, and the Rule 10b5-1 caveat on large sales. This is well beyond what annotations provide.

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?

Front-loaded with the purpose and tightly written, but the middle is one dense semicolon-chained sentence covering counting rules; it is long, yet most clauses carry information an agent needs. Slightly heavier than necessary but no padding.

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, and the description fully enumerates the returned structures (totals, largest sellers/buyers with role/company/dates/holdings, most-bought/sold companies, by-role and by-month totals, first Form 3 filers). Combined with the default and range semantics, an agent has everything needed to call and interpret it.

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%, so both parameters are already documented. The description nevertheless adds meaning the schema lacks: why the default is the last *closed* quarter, what `quarter: 'current'` means ('the quarter in progress, to date'), and the range floor (Q3 2024). The `limit` parameter is left to 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 a specific verb and resource ('Returns the purchases and sales that executives, directors and 10% owners ... reported on SEC Form 4 for one quarter') and enumerates the exact contents returned. It explicitly separates itself from siblings get_ownership (one company) and get_holders (one person), so an agent can route without opening either schema.

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 an explicit trigger ('Use it when the user asks what insiders bought or sold in a quarter') plus two named alternatives with the condition that selects them: get_ownership for one company, get_holders for one person. Nothing is left to inference.

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