Get category spending averages

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

Annotations already declare readOnlyHint=true, so the safe-read nature is covered. The description adds exclusions ('transfers and income excluded') and clarifies positive spending, which enriches the data semantics. However, no details on return format, sorting, or how monthly incompleteness is handled beyond the schema note.

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 tight sentences convey purpose, statistical nuance (median rationale), and exclusions. Zero fluff; every clause earns its place. Perfectly front-loaded with the core action first.

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 single-param, read-only analytics tool with no output schema, the description is nearly complete: it names the metrics, the window, and the exclusions. Minor gap is no mention of whether incomplete current partial months are truly excluded on top of the running-month exclusion, but that is largely redundant with the schema description.

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 100% and months_back is well documented (type, default 6, min 1, max 24, 'Complete months to analyze, running month excluded'). The description complements by framing the metric semantics (average/median/max) and adding the exclusion context ('transfers and income excluded'), adding value beyond the schema.

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?

Clear verb+resource+scope: 'per-category spending average, median and max over last N complete months.' Explicitly positioned as 'input for budget preparation.' Distinguishes from siblings like get_spending_summary by specifying per-category breakdown and multiple metrics.

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?

States it covers 'last N complete months' with the running month excluded (in schema). Median justification ('resists anomalous months') gives agent reasoning for use. Notes exclusions ('transfers and income excluded'). No explicit when-not or alternative naming, but the context is clear enough for a read-only analytics tool.

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