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

Annotations cover read-only/idempotent/non-destructive safety, and the description goes well beyond by disclosing response-side behavior: non-existent ids land in missing_ids, out-of-plan-scope ids in restricted_ids, 404 OWNERSHIP_HOLDING_NOT_FOUND only when none exist, and the credit cost formula ceil(n/5) x 10 (max 200). This gives the agent accurate expectations for error and cost 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?

Four dense sentences, front-loaded with the operative purpose and companion relationship, then error behavior, cost, and endpoint reference — every sentence earns its place and nothing is redundant.

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 no output schema, it covers the return shape (full rows nested under filings), error/edge cases, and cost, which is enough to call it correctly. It falls just short of fully specifying the holding-row fields or the shape of the missing/restricted lists, but the description is largely complete.

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% with all three params documented, so the baseline is 3; the description adds genuine extras — the deduplicated-id count used for credit calculation and the missing/restricted id classification, which clarify what actually happens to invalid or out-of-scope holding_ids beyond the schema's '1-100' range note.

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 (fetch full holding rows by holding id, up to 100, nested under filings) and explicitly names its companion get_initial_holding_stats, distinguishing it from the many list/search siblings. The title reinforces the Form 3 by-id scope.

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?

Explicitly frames when to use it: as the companion of get_initial_holding_stats, when you hold holding_ids from that tool's list and want the full rows behind a figure. However, it never names alternatives for other scenarios (e.g., search_initial_holdings or list_initial_holdings), so there are no explicit when-not/exclusions.

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