spending_by_category

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

No annotations are provided, so the description carries the full burden. It discloses two genuinely useful behavioral facts: the default date window and that internal transfers between one's own accounts are excluded from totals. It does not state read-only nature explicitly, permission requirements, or the shape of the returned per-category figures.

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?

Two short sentences with no filler; the core operation is front-loaded and the exclusion clause follows. Every clause carries 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 read aggregation tool with fully documented parameters and no output schema, the description covers the operation, defaults, and one important filtering caveat. The main remaining gap is the shape of the result (per-category totals keyed by category), which the schema does not supply.

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%, so all three parameters (budget_id, since_date, until_date) are already documented, making 3 the baseline. The description restates the date-range default but adds nothing about date format or the budget_id 'last-used' sentinel, and its 'current month so far' phrasing sits slightly awkwardly against the schema's 'no upper bound' default for until_date.

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 and resource ('Reports total spending per category') plus the scoping dimension (date range), so an agent can distinguish it from listing tools like list_categories or summary tools like get_month_summary. It does not explicitly name which sibling to prefer, but the purpose itself is unambiguous.

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 implies its usage context by noting the default range ('defaults to the current month so far'), which signals the common call pattern. However, it never says when to choose this over alternatives such as get_month_summary or list_overspent_categories, so the guidance stays implicit.

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