Get account balance

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond annotations: USD denomination, the meaning of balance_settled_usd excluding still-settling payments, pending counts, and the 30-day reporting window. It does not discuss auth or rate limits, but for a read-only aggregate with rich annotations this is solid.

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 appropriately sized for a zero-parameter report tool and front-loads the core scope. The first sentence is a fragment and 'Reports page' appears twice, but the second sentence efficiently enumerates the returned data without obvious filler.

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 needs to explain what comes back, and it does: balance, saved payment method count, pending refunds/returns, and last-30-day label count/total/average/payments. It also clarifies the settling caveat on balance_settled_usd. It could be more precise about return field names and structure, but it is complete enough for an agent to understand the tool's output.

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?

The tool has zero parameters, so the baseline is 4. There are no parameter semantics to clarify, and the description appropriately does not invent any.

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 identifies a specific aggregate read: account balance, pending refunds/returns, saved payment methods, and last-30-day label metrics from the Reports page. It is not a bare restatement of the name, though it is phrased as a noun list rather than a clear action. It broadly distinguishes itself from list-oriented siblings by describing a combined Reports-page summary, but does not explicitly name alternatives.

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?

Usage is implied by 'from the Reports page' and by the aggregate nature of the returned data. However, the description does not state when to use this tool instead of siblings such as list_refunds, list_return_labels, list_transactions, or get_shipping_stats. No explicit exclusions or routing guidance are provided.

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