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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, and openWorldHint=false. The description reinforces idempotency by naming op_key and noting the same token is returned, which clarifies the return value somewhat, but it omits auth/permission requirements and what a credential actually grants.

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 the core action front-loaded and no filler. The second sentence is compact and useful, though 'token' is introduced without definition, leaving a slight ambiguity.

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 single-parameter tool with no output schema and full schema coverage, the description is minimally adequate. It does not explain what the returned credential can be used for, its lifetime, or whether it must be stored, all of which matter for a credential-creating tool.

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 op_key description in the schema already documents length bounds and idempotent retry behavior. The description's 'Retry with the same op_key' only restates what the schema parameter description already covers, so it adds no new parameter meaning.

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?

States a specific verb and resource ('Create an additional credential for your identity') and the word 'additional' hints that this supplements rather than replaces existing credentials. It does not, however, distinguish itself from close siblings such as create_capability, recover_credential, or revoke_credential, which an agent may confuse with it.

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 no when-to-use guidance, no prerequisites (e.g., existing identity/auth requirements), and no comparison to alternatives like recover_credential or revoke_credential. The retry note is about invocation mechanics, not about when to choose this tool.

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