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

Annotations already declare readOnlyHint and idempotentHint, so safety is covered. Beyond that, the description discloses the concrete response shape: filing-linked rows and a next_tools field that routes deeper questions — useful context an agent cannot get from the schema. It stops short of describing result limits or row-cap behavior.

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?

Two dense sentences, front-loaded with the imperative 'START HERE', then the payload inventory. Every clause carries information; no filler or restatement of the name.

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 carries the return-value burden and does so: it names the four data categories and the filing-link/next_tools structure. Combined with annotations covering safety and a fully documented parameter schema, an agent has everything needed to call it 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%, and the schema itself fully documents both parameters, including the precise definition of an open-market buy. The description only restates 'ticker or company name', which is narrower than the schema's broader identifier formats, so it adds little beyond the structured data. Baseline 3 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 specific verb and resource ('one call returns the full insider picture for a ticker or company name') and enumerates exactly what is aggregated: 13D/13G stakeholders, Form 4 activity, Form 144 sales, and 8-K events. It clearly distinguishes itself from the focused siblings (get_stakes, get_insider_trades, get_planned_sales, get_material_events) as the aggregating entry point.

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?

'START HERE for any company question' gives an explicit, unambiguous invocation rule and frames the tool as the entry point before drilling down. It does not name the sibling alternatives directly (it delegates that to the response's next_tools field), so the routing is directional rather than enumerated.

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