Summarize income and spending for a period

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

With no annotations provided, the description carries the burden of behavior disclosure. It clearly says the tool aggregates across all accounts over a month or date range and returns a financial summary, which implies a read-only analytical operation. It doesn't explicitly state 'does not modify data' or discuss authorization, but the behavioral scope is reasonably transparent.

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 only two sentences, front-loads the core aggregation behavior, and includes a compact usage example at the end. Every phrase contributes meaning and there is no redundant padding.

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?

Although there is no output schema, the description lists the key return components: total income, total spending, net, per-account breakdown, and largest transactions. The period-selection behavior is clarified between month and explicit date range, making the tool fully invocable without missing critical context.

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 input schema already documents all four parameters with 100% coverage, so the description is not required to repeat parameter details. It does add the high-level notion of 'month (or an explicit date range)' and 'largest transactions', but these align with the schema rather than revealing new semantics. Baseline 3 is appropriate.

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 names a specific verb ('Aggregates') and resource ('every account'), and clearly enumerates the produced outputs: total income, total spending, net, per-account breakdown, and largest transactions. This makes it easy to distinguish from sibling transaction-listing and account-detail tools.

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?

It gives an explicit usage cue: 'Use this for "how did I do this month"', which clearly frames when this summary tool is appropriate. It does not name specific alternatives or state when not to use it, so it stops short of a full when/when-not comparison.

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