Get client balance

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

Annotations already establish the read-only, idempotent, non-destructive nature. The description adds useful behavioral context beyond that by explaining that the balance is specifically the sum of open invoices and that status counts are included. It does not describe the exact response shape, but the annotations lower the burden for safety-related behavior.

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 three concise sentences with no filler. It front-loads the primary result, then adds implementation detail and a routing hint, with every sentence contributing useful 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?

For a simple read-only tool with two well-documented parameters and no output schema, the description conveys the core return value and important context about how the balance is calculated. The status list is abbreviated with '...', which leaves some ambiguity, but the overall guidance is sufficient for an agent to decide whether to call this tool.

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 meaning beyond the schema by explaining that the currency parameter is the currency in which the owed amount is expressed. It also points to get_client for discovering the client's default currency, which clarifies the intended use of the currency parameter.

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: it returns the amount a client owes in a given currency (sum of open invoices) plus invoice counts by status. It also distinguishes itself from related tools by explicitly referencing the underlying Invoices.amountDue and Invoices.getStatusCount operations.

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 concrete guidance for a related task: 'Use get_client with include_settings to learn the client's default currency.' This helps an agent decide between this tool and a sibling when currency information is missing, though it does not explicitly enumerate all alternative tools or exclusion conditions.

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