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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is fully covered. The description adds the meaningful default window (last 30 days) and the aggregation granularity, but says nothing about the café's clock/timezone or what happens when the range has no orders.

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?

A single compact sentence that front-loads the headline question (when is it busiest) and then lists the breakdowns. Dense but every clause carries information; no filler.

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?

With no output schema, the description compensates well by enumerating the returned aggregations, and the default window is stated. The remaining gap is minor: no note on empty results or how the café's clock affects bucketing, but an agent has enough to call it correctly.

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%, so parameters like from/to overriding period, café fallback to list_my_cafes, and branch scope are already documented. The description contributes one genuine extra fact — the default period of last 30 days — which the schema does not state, so it sits at the baseline rather than below or above it.

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 names the resource (busy times) and spells out three concrete outputs — orders by hour of day, busiest half hour, and orders/sales by weekday — so an agent knows exactly what it gets back. It is clear without explicitly distinguishing itself from neighbours such as get_sales_summary or get_top_items.

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 only implied through "Useful for rotas and opening hours", which frames the staffing/planning scenario. There is no explicit statement of when to prefer this over get_sales_summary or get_live_status, and no exclusions or prerequisites.

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