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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds crucial context beyond these: 'Data delayed 24 hours (known_at); history ~1 month; no price-derived fields.' It also explains why event classification matters, which gives the agent a deeper understanding of the tool's behavior and limitations.

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?

The description is concise yet rich, with four sentences that each deliver unique value: purpose, classification logic, filtering/pagination, and exclusions/caveats. It is front-loaded with the core function and ends with operational constraints. No sentence is wasted.

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?

Given the tool's complexity (6 optional params, output schema, annotations), the description is complete. It covers data source, interpretation logic, filtering capabilities, pagination, alternative tools, data freshness, retention window, and absence of price-derived fields. The agent has enough context to select and invoke the tool 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?

The input schema covers 100% of parameters with descriptions, so the baseline is 3. The description mentions filtering by ticker, event type, minimum USD value, and time, but these are already in the schema. It does not add any new semantic meaning beyond the schema, so this meets the baseline but does not exceed it.

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 clearly states 'Search interpreted insider-trading events from SEC Form 4 filings' with a specific verb and resource, and distinguishes itself from siblings by noting 'Form 4 only' and naming alternative tools. It precisely differentiates the tool's scope from get_activist_stakes, get_sale_notices, and get_company_timeline.

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?

Explicit usage guidance is given with 'Form 4 only - for 13D/G stakes or Form 144 sale notices use get_activist_stakes, get_sale_notices, or get_company_timeline.' Also, the description explains the tool's value (separating discretionary trades from compensation noise) and the event_type parameter description advises 'Use OPEN_MARKET_BUY for discretionary insider buying.' This clearly tells when and when not to use the tool.

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