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

No annotations are provided, so the description carries the disclosure burden. It does useful work by describing the response shape (totalCash, availableCash, and converted ref* fields), but says nothing about read-only nature, permissions, or freshness of the balance 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?

Three short sentences, front-loaded with the core definition before the response detail and the use-case hint. No filler, though the third sentence is more of a nice-to-have than essential information.

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 usefully explains what each entry contains and the base-currency conversion, covering the main return-value gap. For a simple read tool it is nearly complete; only permissions and read-only confirmation are absent.

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%: both portfolioId and currencyCode are documented in the schema, including the 'omit to return all currencies' behavior. The description adds no parameter-level detail beyond what the schema already provides, so the baseline of 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 (get) and resource (cash balances in a portfolio), plus the scope (broken down per currency). An agent can tell this apart from holdings/summary tools in spirit, but the description never names the closest siblings (get_portfolio_holdings, get_portfolio_summary), so differentiation is implicit rather than explicit.

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 closing line gives an implied use case ('how much cash do I have to invest'), which signals when to reach for it. There is no explicit when-not guidance and no named alternative for portfolio value or holdings questions, so routing still requires inference.

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