spending_by_category

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

With no annotations, the description carries the transparency burden. It discloses that the tool aggregates (sums) and groups by category, and 'Shows where money goes' adds interpretive context. However, it does not clarify behaviors like inclusion of zero-activity categories, handling of uncategorized transactions, or read-only assurances.

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 short sentences with no filler. It front-loads the core function and keeps the secondary interpretive statement brief, earning a high score for conciseness.

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?

Given no output schema and no annotations, the description is minimally sufficient but leaves gaps: it does not describe the return shape (e.g., a list of category-total pairs), sorting, or behavior when there is no spending. It covers the core purpose but lacks supporting details.

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 schema already provides full descriptions for all three required parameters (dateFrom, dateTo, accountId) with 100% coverage. The description adds no additional parameter-level detail beyond the phrase 'for a date range,' so it stays at the baseline.

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-resource pair ('aggregate spending by category') and a date-range qualifier, clearly distinguishing it from siblings like top_merchants or search_transactions. It unambiguously explains what the tool does.

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 usage for analyzing spending by category over a given date range, but it does not explicitly mention when to prefer this tool over alternatives like cashflow_summary or top_merchants, and provides no exclusions or alternative suggestions.

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