Account Balance

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true, so the description's main behavioral disclosure is that it returns 'cash balance and asset summary'—this adds context about the return type but does not contradict annotations. No additional behavioral traits (e.g., pagination, error behavior) are disclosed, which is acceptable given the tool's simplicity and the strong annotation coverage.

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 exceptionally concise: two sentences that immediately state the tool's purpose and parameter behavior. Every word serves a purpose, and the structure is front-loaded with the core function. There is no extraneous information, making it ideal for an AI agent to quickly interpret.

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?

Given the tool's simplicity (one optional parameter, no output schema), the description adequately covers the essential aspects. It states what the tool returns ('cash balance and asset summary') and how to use the filter. However, it does not describe the exact format or fields of the return value, which would improve completeness. Still, it is sufficient for basic usage.

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 schema provides a description for the 'currency' parameter that is nearly identical to the description's guidance. The description adds example values ('USD', 'HKD') and clarifies that omitting the parameter returns all currencies, which slightly enhances understanding. With 100% schema coverage, the description adds marginal value, earning a baseline of 3.

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 clearly states the tool's function: 'Get account cash balance and asset summary.' It uses a specific verb ('Get') and resource ('account cash balance and asset summary'), making the purpose immediately understandable. The optional currency filter is clearly explained, and the tool is distinct from its many siblings, as it uniquely focuses on account-level balance information.

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 provides basic usage guidance for the parameter: 'Pass currency to filter; omit to return all currencies.' However, it does not mention when to use this tool versus alternatives (e.g., broker_holding, stock_positions) nor any prerequisites or exclusions. The guidance is adequate for parameter usage but lacks broader context for tool selection.

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