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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description's 'a read-only report' largely restates structured data. It does add one genuinely useful nuance — that this read operation is exposed as POST /statistics/reports — which prevents an agent from assuming the HTTP verb implies a write. Beyond that, no rate limits, permission requirements, or cost/aggregation caveats are disclosed.

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?

One front-loaded sentence carries the purpose, with a short parenthetical noting the upstream endpoint. Appropriately sized with no filler, though the endpoint note is marginally redundant with the read-only annotation.

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 correctly names what is returned (total messages and total price, broken down per country) plus the optional type filter. That covers the essentials for a read-only report tool; only the return shape/units of 'price' are left unstated.

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 the schema already documents start_date, end_date, and message_types with formats and enum values. The description only confirms the optionality of message_types and the date-range scope, adding little beyond the structured fields — the expected baseline here.

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+resource ('Get total messages and total price per country') with aggregation granularity and scope (date range, optional message types), which cleanly separates it from siblings like get_prices and get_delivery_status. It never names an alternative sibling explicitly, but the resource is unambiguous.

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?

There is no when-to-use guidance, no exclusions, and no mention of the closest sibling (messente_get_prices). The only usage-ish signal is that message_types is optional, which is really parameter information rather than routing guidance.

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