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

Annotations already declare a safe read operation, but the description adds material context beyond them: a sign-in is triggered for unauthenticated callers, Professional plan access is required, ISIN/CUSIP positions are refused outright, and matching is exact with no guessing. These are exactly the operational traits the annotations do not cover.

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 purpose and identifier rules are front-loaded, then outcomes, then access/auth, which is a sensible order. It is dense and long, but nearly every clause carries distinct information about outcomes or constraints rather than padding.

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 return-value burden and does so by enumerating all five outcomes (resolved, ambiguous, withheld, uncovered, out_of_scope), the fields on a resolved result, and the reason_code on the rest. Access and auth requirements round out what an agent needs 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 coverage is 100%, so the baseline is 3, but the description adds real meaning: it enumerates the accepted identifier kinds, explains that module_hint narrows an ambiguous outcome to a candidate module, and clarifies position_ref is echoed but never used to resolve. This goes beyond restating the schema.

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: map positions to ACI Risk Indicators of the providers behind them, and it fixes the scope at up to 200. That is clearly distinct from sibling tasks like get_risk_score or assess_portfolio_risk, so an agent can select it without opening the 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?

It gives strong in-scope conditions (positions carry identifiers only, market values not accepted) and states the plan requirement, which effectively implies usage context. However, it never names an alternative sibling or explains when to prefer this bulk mapper over get_risk_score or assess_portfolio_risk, leaving routing to inference.

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