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

Annotations already cover readOnly, idempotent, and non-destructive behavior. The description adds substantial behavioral context beyond that: it explains that code P is the only own-money buy signal, that A/M/F are automatic compensation, that form=144 is an intent-to-sell signal, and that 'latest' returns the biggest open-market buys. This significantly enriches the agent's understanding of the tool's 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?

The description is three sentences but packs dense, high-value information. It front-loads the core function in the first sentence, then explains transaction codes and special modes. Every clause earns its place; no filler or repetition.

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?

For a tool with 5 parameters and no output schema, the description covers all major aspects: return fields, parameter behavior, special modes, and the meaning of transaction codes. It also mentions defaults for 'days' and 'min_insiders' implicitly through schema, and the description is self-sufficient for an agent to decide when and how to invoke 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?

Even though the schema covers 100% of parameters, the description adds meaning beyond the schema by explaining special values for 'ticker' ('latest' and 'clusters') and the semantic difference between form types. It also clarifies the business meaning of transaction codes, which is not in the schema. This raises the score well above the baseline.

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 opens with a specific verb and resource: 'Parsed SEC Form 4 insider trades for a ticker'. It lists exact data fields (owner, role, transaction code, shares, price, dollar value, 10b5-1 flag) and distinguishes itself from siblings like get_filings by focusing on parsed insider transactions and offering unique special modes ('latest', 'clusters').

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 provides clear context for when to use each alternative: it explains the transaction code meanings (P vs A/M/F), directs users to form=3/5 for holdings statements and form=144 for proposed sales, and explains special ticker values 'latest' and 'clusters'. However, it does not explicitly name sibling tools or state when NOT to use this tool, so it falls just short of a 5.

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