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

Annotations already establish readOnlyHint and idempotentHint, so the safety profile is covered. The description still adds substantive behavioral detail beyond the annotations: the precise buy filter (code P, acquisition, non-derivative, price > 0, not offset by same shares at same price) and the sort order (total value), which meaningfully define what the result set contains.

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?

A single dense sentence with the tool's core purpose front-loaded and the parenthetical filter conditions compactly packed. Slightly heavy in one breath, but every clause earns its place by narrowing the result set.

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 should describe what comes back; it only says results are 'sorted by total value' without naming returned fields (issuer, insider count, combined value, dates). Acceptable for a read-only filter tool but leaves a real gap on the return shape.

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 baseline is 3. The description's phrasing clarifies that the window operates on transaction dates and that insiders must be distinct, modestly reinforcing window_days and min_distinct_insiders, but it adds no format or range guidance beyond 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?

The description states a precise verb+resource (find issuers with clustered insider open-market buys) and enumerates the exact qualifying conditions, making it clearly distinguishable from siblings like get_insider_trades or get_stakes. An agent can tell what output population this returns without opening the 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?

It supplies clear context for when this is the right tool: a derived signal ('a signal raw EDGAR cannot answer') that raw filing lookups cannot produce. However, it never names an alternative sibling or states an explicit when-not-to-use condition, so routing is inferred rather than spelled out.

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