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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description adds valuable context beyond that: cost per call, the payment-required error behavior for unpaid calls, the analytical meaning of cluster buying, and a disclaimer that it is not investment advice.

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 compact and front-loaded, starting with the core deliverable and then adding the signal context, routing advice, disclaimer, and cost/error behavior. Every sentence contributes useful information without fluff.

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 a detailed description, complete parameter documentation, and an output schema present, nothing essential is missing for correct invocation. Cost, error handling, prerequisite lookup, and alternative routing are all covered.

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 both cik and months are already well documented. The description does not add much parameter-level detail beyond reinforcing the trailing-month window, so the baseline of 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 exactly what the tool provides: Form 4 insider transactions for a single company over a trailing window, with a summary of open-market buys vs sales, distinct buyers, net dollar value, and 10b5-1 plan flags. It clearly distinguishes itself from company_signal by framing that tool as the scored-conviction alternative.

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?

The description explicitly routes the agent to company_signal when scored insider conviction is needed, and the parameter description tells users to call lookup_company first if they only have a ticker or name. This provides clear when-to-use and when-to-use-alternative guidance.

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