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. The description adds genuinely useful non-schema context — 5 prepaid credits and a production billing requirement — which an agent needs before invoking. It stops short of describing output, detection thresholds, or what counts as "repeated."

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 sentences, front-loaded with the core action and followed by the billing constraint. No filler, though the "bounded event window" phrase adds ambiguity rather than information given the schema.

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?

For a paid, single-array-parameter analytic tool with no output schema and no parameter documentation, the description leaves the input shape and the return value undefined. The cost disclosure is helpful, but an agent cannot confidently construct the nonces payload from this definition.

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?

The single required parameter has 0% schema description coverage, so the description must carry the load and largely fails. It never explains whether elements are bare nonce strings or objects carrying nonce plus timestamp/event metadata, even though a "bounded event window" implies the latter.

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?

"Detect repeated nonce values" gives a specific verb and resource, which is clearly distinct from siblings like privi_nonce_generate or privi_pro_duplicate_events at a glance. The qualifier "within a supplied bounded event window" is somewhat confusing since no window parameter exists, but the core action 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 guidance on when to choose this over related risk tools (e.g. privi_pro_duplicate_events or privi_nonce_generate), nor on prerequisites for the nonces input. The billing note is a constraint, not usage guidance.

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