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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description adds real value beyond that by disclosing the Pro-plan gating and the unit convention for returned values (fractions, 0.05 = +5%). It stops short of covering edge cases such as insiders with no transactions, response size, or how the median is computed over sparse data.

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?

Front-loaded with the core action and the field list, then usage routing, then prerequisites — a sensible order. The long enumerated field list is dense but each item tells the agent what comes back in the absence of an output schema, so it largely earns its space; the fraction note is stated twice (description and schema), which is minor waste.

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 burden of describing return contents and does so by enumerating the rollup fields and their units. It also names the plan requirement and the companion tool. It lacks only edge-case behavior (empty results, error conditions) for a full 5.

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% on the single cik parameter, and the schema already explains the leading-zero tolerance, the Tim Cook example, and the fraction convention. The description only repeats the CIK scoping and the fraction note, adding essentially no parameter meaning beyond the schema; baseline 3 applies.

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?

States a specific verb and resource ("aggregate career rollup for one insider by CIK") and then enumerates the exact contents of the rollup: first/last transaction dates, shares/value bought vs sold, top companies, transaction-code breakdown, 10b5-1 split, median post-trade returns. It also names the sibling it replaces (get_insider_transactions), so an agent can separate it from raw-row and scorecard tools without opening either 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?

Gives an explicit selection rule: use this instead of get_insider_transactions when a pre-computed summary is wanted rather than raw rows, and pair with get_insider_scorecard for hit-rate stats on discretionary buys. It also states the prerequisite (Pro plan) and the input prerequisite (resolve a name to CIK via search_insiders), which is unusually complete routing guidance.

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