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 known. The description adds two genuinely useful behavioral facts beyond the annotations: that values are never returned, only key flags, and that invocation costs 5 prepaid credits with production billing required.

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 compact sentences with no filler. The core behavior is front-loaded, and the billing constraint follows as a secondary but necessary note.

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?

The description covers the essential behavior and the cost, and the absence of an output schema is partly offset by the statement that values are not returned. However, an agent still cannot predict the result shape, such as whether it receives key paths, key names only, or a count, and the nested-payload handling is left undefined.

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 schema has 0% description coverage and only one nested object parameter, so the description must carry the meaning. It does clarify that the payload is nested, but it says nothing about traversal depth, how deeply keys are inspected, or what shape the payload should take.

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 states a specific verb and resource: flagging sensitive-looking keys inside a nested payload. It is clear what the tool does and its key constraint (values are not returned), though it does not explicitly contrast itself with related sibling tools such as a general presence check.

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 tool versus alternatives, or any prerequisite context beyond the billing note. The phrase 'without returning values' implicitly signals a privacy-safe use case, but that is left for the agent to infer.

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