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

Annotations already declare a safe, idempotent read, so the bar is lower, yet the description adds substantial behavioral context: daily updates, 200-row cap with pagination via page, price_outlier rows excluded from rankings/totals, carried_from semantics for Form 4/A amendments, and rule_10b5_1 null before 2023. These are non-obvious traits an agent could not infer from the schema.

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 purpose and a dense but largely waste-free paragraph; nearly every sentence carries field semantics or a constraint. It would be more scannable with structure, and the back-half semantics (carried_from, price_outlier) could be tightened, but there is little filler.

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 an output schema present, the description need not explain return shapes, yet it still covers row granularity, aggregation rules, date formats, null conditions, and pagination limits. For a 10-parameter tool with zero required params, this is fully sufficient to call it 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?

Schema description coverage is 100%, so a baseline of 3 applies, but the description goes further by enumerating the meaning of each transaction code (P, S, A, D, F, G, M, X, C, W, J) and restating the default codes P and S, which the schema only lists as values. It also clarifies that 'without ticker or insider_cik' triggers a 30-day market-wide limit, adding conditional meaning to those params.

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 ('Insider transactions from SEC Form 4 filings') and immediately scopes it with coverage start and update cadence. It is easily separable from siblings like get_insider_lists and get_superinvestor_activity, which cover different data.

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 clear usage context: 'Filter by ticker, insider_cik, filing-date range, codes, the primary insider's role and minimum value,' and explains that omitting ticker/insider_cik yields a market-wide query capped at 30 days, defaulting to the last 7. However, it never names or routes to an alternative sibling tool, so it falls short of explicit when-to-use-vs-alternative guidance.

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