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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds the upstream source (Uptime Kuma) which is useful context, but says nothing about what happens when no heartbeat data exists for the window or whether outages are truncated — gaps an agent would care about for a monitoring read.

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 that lists outputs in priority order with no filler. The trailing source phrase is slightly redundant given the tool name but costs little.

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?

An output schema and rich annotations carry most of the burden, and the description covers the metric set. Still missing is how the look-back window intersects with the reported fields and any precondition on site naming, which matters given siblings like check_site_name and get_site_status.

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 the hours parameter already documents its 1–72 range and default. The description implies a look-back window via 'recent outages' but adds no new meaning, such as whether hours applies to all three metrics or only outages.

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?

Names a specific verb and resource ('get_site_uptime') and enumerates the returned metrics — uptime percentage, average response time, recent outages — plus the data source (Uptime Kuma heartbeat monitor). It does not explicitly contrast with the closest sibling, get_site_status, so it falls short of a 5.

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 by the metric names; there is no statement of when to prefer this over get_site_status, get_site_analytics, or get_site_traffic, nor any note that the site must exist (check_site_name) before calling.

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