spending_by_category

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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds that the tool returns total spending and percentage per category, which is useful context. However, it does not disclose details like whether transfers are excluded, how percentages are calculated, or what happens with zero-spending categories – gaps made less severe by the read-only annotation.

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 two sentences with no filler. It leads with the core action, then states the output content. Every sentence earns its place, and the length is appropriate for the tool's simplicity.

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 read-only aggregation tool with fully documented parameters, the description is adequate but not complete. It mentions the output (totals and percentages) but omits any mention of how percentages are computed, whether the output is sorted, or how the limit parameter affects results. Since there is no output schema, a bit more detail on return semantics would improve completeness.

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 description coverage is 100%, with all four parameters (limit, end_date, start_date, include_income) documented in the schema. The description adds no parameter-specific details beyond the general 'date range' phrasing, so it does not exceed the baseline set by complete schema coverage.

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 uses a specific verb ('Break down') and resource ('spending by category'), and details the output ('total spending and percentage of total'). It clearly states what the tool does, though it does not explicitly differentiate from overlapping siblings like category_trends or budget_vs_actual, which also aggregate spending.

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?

No guidance is given on when to use this tool versus alternatives such as category_trends, monthly_summary, or budget_vs_actual. The description only states the tool's function, leaving the agent to infer appropriate usage from the name and sibling list.

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