top_payees

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

With no annotations, the description carries the full burden and does add real behavioral context: it discloses that inter-account transfers are excluded and that the window defaults to the current month so far. It does not mention ordering guarantees, rounding, or what happens when a payee has zero spend, but the key filtering rule is stated.

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 sentences, zero filler, with the core function front-loaded and the exclusion rule appended as a scoping caveat. Nothing here is redundant.

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 with full parameter documentation and no output schema, the description conveys the grouping key, sort intent and default window, which is enough to call it correctly and interpret the result shape. Minor gaps (e.g., whether results are truncated by limit only) remain but are not blocking.

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 limit, budget_id, since_date and until_date are all documented in the schema itself. The description only echoes the date-default behavior already stated in the schema, adding no new syntax or format detail beyond it — the baseline 3 applies.

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 grouped by payee' — plus the ranking intent ('who you spend the most money with'). It implicitly distinguishes itself from spending_by_category by the grouping key, but never names or contrasts the sibling explicitly.

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?

Usage is implied by the grouping ('grouped by payee') and the default window, so an agent can infer when it fits. However, there is no explicit when-to-use/when-not guidance and no alternative named among siblings like spending_by_category or spending_trend.

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