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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the mutation/safety profile is covered. The description adds the single most important behavioral fact beyond that: "the raw key is shown once," warning the agent that the secret is unrecoverable after the response and must be surfaced immediately. It does not mention permission requirements or whether created keys can be revoked.

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 action and followed by the critical caveat. Every clause carries 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?

With no input parameters and no output schema, the description covers the essentials: what is produced, the key format, and the one-time visibility of the raw value. It leaves open the default scope/expiry of the minted key, which is the only notable gap for a zero-input 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?

The tool takes zero parameters, so the schema-based baseline of 4 applies. The description correctly implies a bare invocation with no input configuration, and adds nothing misleading about inputs.

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?

"Mint a pf_ caller key" gives a specific verb (mint/create) and resource (caller key), plus the key prefix format. The sibling tools (explain_extractor, extract, extract_batch) are unrelated to key management, so no sibling differentiation is needed or possible here, which keeps it just shy of a 5.

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 states what the tool does but never says when to call it — no mention of prerequisites (admin/auth requirements), no guidance on how many keys to create, and no alternatives to consider. An agent must guess whether this is a routine step or a privileged one-off action.

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