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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so 'No mutation' merely restates structured data. Nothing is added about the time window the report covers, how the breach flag is computed, or what happens for meters with no usage.

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, front-loaded fragments with no padding, and the core comparison is stated first. The trailing 'No mutation' is redundant with the annotations and is the only wasted text.

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 exists, so return values need not be described, and annotations cover the safety profile. However, for a metric-reporting tool the description leaves out the reporting period and what to expect when a meter has no data, which an agent needs to interpret results.

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 0% and the sole required parameter, meter_id, is never explained in the description. An agent must infer that meter_id comes from list_meters and whether it is a name, UUID, or numeric id; nothing in the description compensates for that gap.

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?

The description names a specific resource and output shape: an SLA report comparing success_rate against sla_target with a breach flag. That is enough to separate it from siblings like usage_summary and usage_timeseries, though the verb is implied rather than stated outright.

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 and no mention of when the agent should prefer usage_summary or usage_timeseries instead. The only usage signal is the word 'Pure', which hints at a read-only analytical report but does not say when that is the right choice.

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