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

Annotations already declare readOnlyHint=true, so 'Read-only' restates structured data rather than adding context. The description does clarify that both endpoint dates are inclusive and that results are bucketed by day, which is genuinely useful, but says nothing about openWorldHint implications, rate limits, or what an event with no sales returns.

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, front-loaded with the outcome and grain, no filler. The trailing 'Read-only.' is redundant with annotations and earns little, which keeps it just below a 5.

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?

There is no output schema, so the description carries the burden of explaining the result shape. 'Ticket sales per day' hints at day-bucketed rows but never says what fields come back (date, count, revenue) or whether empty days are included — a meaningful gap for an analytics tool.

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% with all three params documented, so the schema does the heavy lifting. The description only reinforces the YYYY-MM-DD format and makes the inclusive boundary explicit — baseline 3 is right for this level of added meaning.

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 with an explicit grain ('ticket sales per day for an event') plus the range shape. That aggregation grain already separates it from the get/list siblings, though it never names an alternative 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 only implied: it's clearly the analytics rollup over an event's sales while universe_list_orders/universe_get_order would supply raw records, but the description never says so or states when-not to use it. Inclusive-boundary semantics is the only real guidance offered.

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