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

The description discloses the key behavioral consequence—the current key is invalidated—which goes beyond what readOnlyHint=false alone conveys. It could additionally note that existing clients using the old key will stop working, but 'invalidate' already makes the effect clear.

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 with no filler: the first states the operation, the second states the trigger. The action is front-loaded and every word earns its place.

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 low-complexity tool with one optional, well-documented parameter and no output schema, the description is largely complete. The only minor gap is that it does not explicitly state that the new key is returned, though 'issue a new key' implies it.

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 schema's api_key description already explains when to include or omit the parameter. The tool description adds no extra parameter semantics, so the baseline score of 3 applies.

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 action ('Issue a new key and invalidate the current one') that clearly distinguishes rotation from plain key lookup or creation. It does not name or contrast sibling tools such as recover_key, so it falls just short of perfect differentiation.

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?

'Use if the key may have leaked' gives a clear and actionable trigger condition. It does not mention exclusions or alternative tools, so there is no explicit when-not-to-use guidance.

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