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

Annotations already establish readOnly, non-destructive, closed-world behavior, so the description is free to add analytical context instead of repeating safety. It does so meaningfully by disclosing the interpretation of the result: whether FX cash offsets invoice exposure in the same currency. It still omits freshness/refresh behavior of the balances, which keeps it short of a 5.

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?

Two sentences, front-loaded with the core capability, and the second sentence earns its place by explaining the analytical value of the result rather than padding. No redundant restatement of the name or schema.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile. Purpose and interpretation are well covered; the remaining gap is routing guidance versus related reads such as get_fx_exposure or get_cashflow_forecast.

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 all three parameters (currency, entity_id, include_chart) are already documented with pattern, default, and chart rendering detail. The description adds only a loose 'by currency and entity' restatement and no new parameter semantics, so the baseline 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 and resource ('Returns current cash balances') plus the dimensions of the result (by currency and entity). It is distinguishable from forecast siblings like get_cashflow_forecast by the word 'current', but it does not explicitly name a sibling or draw the boundary against get_fx_exposure.

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 gives no when-to-use guidance, no prerequisites, and no named alternatives. The only usage hint ('Omit for group-level consolidated cash position') lives in the entity_id schema field, not the description, so the prose itself carries no routing information.

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