Spending / income report

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

Annotations only declare readOnlyHint=true and openWorldHint=false, so the description carries the behavioral load and does it well: exclusion of transfers/debt types, currency conversion at current rates, and the default in-balance account filter with an override. It stops short of describing the response shape (groups, totals, counts, shares ordering) or the effect of the top roll-up.

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?

Three sentences, front-loaded with the core capability and grouping options, with no filler. It is dense and each clause carries information, though the trailing 'like ZenMoney reports' reference adds minimal operational value.

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 17-parameter tool with no output schema, the description covers the key semantics an agent needs: what gets aggregated, what is excluded, currency conversion, default account scoping, and that the output contains totals, counts and shares. Remaining gaps (how top groups are rolled up, exact return structure) are modest.

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 high (88%), so the baseline is 3, but the description adds meaning the schema lacks — notably the semantics of measure=both (income + expense + net cash flow) and the relationship between include_off_balance and the default in-balance filtering. The undocumented enum for measure is effectively compensated.

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 (aggregate) and resource (expenses/income) plus the full set of grouping dimensions (category, parent category, payee, account, time), which clearly separates it from the raw-listing siblings like list_transactions and from get_overview/get_budget. An agent can identify it as the reporting/aggregation tool without opening the schema.

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?

Provides real selection context: measure=both yields income, expense and net per group (cash flow), transfers and debts are excluded, and only in-balance accounts count by default unless include_off_balance is set. It never explicitly names an alternative tool (e.g. list_transactions for raw rows), so it is clear context without exclusion-vs-sibling routing.

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