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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered and the description is not obliged to restate it. Beyond that it discloses nothing: no formula, no rounding or unit convention, and no behavior when total is zero, even though it is a pure computation whose result depends entirely on that convention.

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 front-loaded sentence with zero filler, correctly leading with the verb and the derived quantity. It is efficient, but the brevity borders on under-specification rather than tightness.

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 needed to say what is returned (0-100 percentage vs. 0-1 ratio, rounding) and does not. Combined with 0% schema coverage on both required parameters and no edge-case behavior, the definition is too thin for a pure calculation 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 0%, so the description carries the full burden, and it only partially discharges it by mapping the two fields to concepts (successful probes, attempted probes). It leaves the critical ambiguity unresolved: whether "total" includes the successful count, and what the numerator/denominator relationship is.

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 ("Calculate") and a specific derived quantity ("availability") with its raw inputs ("successful and attempted health probes"). It does not differentiate itself from the sibling privi_pro_uptime_slo, which also concerns uptime, so an agent cannot tell from the description alone which one computes a raw percentage versus an SLO.

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 or when-not-to-use guidance, no prerequisites, and no mention of the SLO sibling as an alternative. The only hint of context is that the inputs come from health probes, which implicitly limits the tool's domain but gives no routing instruction.

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