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

The description adds rich behavioral context beyond the destructiveHint annotation: it warns that the key is 'IRREVERSIBLY deactivates' and that 'every other caller using that key stops working immediately.' It also discloses that 'the new key is returned exactly once in the response and cannot be retrieved again,' covering side effects and return semantics.

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?

The description is compact and front-loaded, stating the core action first, then issuing a clear WARNING, and ending with essential constraints. Every sentence carries operational information; there is no filler.

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 action, irreversible consequences, impact on other callers, one-time return of the new key, child-key limitations, and authentication. With a single optional parameter documented in schema and an output schema presumably describing the new key, nothing critical appears missing.

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 only parameter expires_in_days is fully documented in the input schema with min, max, and default, providing 100% coverage. The description does not revisit the parameter, so it adds no additional meaning beyond the schema.

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 opens with 'Replace the API key making this call with a fresh one carrying the same scopes,' which precisely identifies the action and resource. This clearly distinguishes it from siblings like get_api_key_info (read-only) and mint_child_api_key (creates a separate key).

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?

The description gives an explicit when-not warning: 'do not call it on a shared credential' and notes that 'a delegated child key cannot rotate itself.' It also states the auth prerequisite, but does not point to alternative tools for creating new keys without invalidating the current one.

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