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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds that the result is an aggregate spanning one or more time ranges, which is useful behavioral context, but says nothing about cost, rate limits, or how multiple ranges are returned.

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 tight sentences with zero waste. The core capability is front-loaded and the usage hint follows immediately, making it easy to scan.

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 does the work of naming what comes back (uptime percentage and response-time statistics). That covers the essentials for a 2-parameter read tool; only details on multi-range output shape are absent.

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 both parameters (check_id and ranges, with its allowed values and default 1d,7d,30d) are already fully documented in the schema. The description adds no syntax or format detail beyond what the schema provides, so 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 (get) and resource (aggregate uptime percentage and response-time statistics for a check), which implicitly separates it from siblings like get_check (config) and get_check_history (raw events). It does not explicitly name those siblings, but an agent can tell the aggregate-statistics purpose apart from the raw-history and config tools.

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?

Gives clear usage context: 'Good for how has this been doing questions and week-over-week comparisons.' This tells the agent when this tool is the right fit versus raw history. It stops short of naming an alternative or an explicit when-not condition.

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