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

Annotations already mark the tool as read-only and idempotent, but the description adds substantial behavioral detail beyond that: method-dependent key naming, zero-cash counting, adjusted-basis share totals, corporate action handling, _warnings semantics, plan history limits, 403 PLAN_TIER_INSUFFICIENT_COVERAGE behavior, and credit cost. No contradiction with annotations.

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 dense but every clause carries operational weight: purpose, paging, requirement, key naming, edge cases, warnings, plan limits, errors, and cost. It front-loads the main purpose and pagination before caveats, with no filler or repeated schema content.

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 13-parameter tool with no output schema, this description is remarkably complete. It covers response-relevant fields (transaction_ids, ids_total, ids_has_more, _warnings, start_date_applied, as_of_date_applied, corporate_action_crossing, corporate_actions), error behavior, plan limitations, and pricing, so an agent can invoke it correctly without external documentation.

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 coverage is 100%, so the baseline is 3; the description adds meaningful cross-parameter information such as how method changes response key names (acquired/disposed vs bought/sold), how ids_page/ids_page_size control transaction_ids paging, and the sibling's 100-ids-per-call cap. This goes beyond the schema's individual field descriptions.

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 action and resource: 'Totals over one company and/or one insider, plus transaction_ids for every contributing row.' It clearly frames this as the aggregation counterpart to get_insider_transactions_by_id, so an agent can distinguish it from sibling tools without opening schemas.

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 tells the agent to feed transaction_ids to get_insider_transactions_by_id for detail and documents the paging mechanism and the 100-id limit of the sibling. It also states the prerequisite combination of ticker and/or insider_cik. It does not explicitly enumerate when not to use this versus other aggregate siblings, but the detail-vs-aggregate routing is clear.

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