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

With no meaningful annotation detail beyond non-read-only and non-destructive, the description carries the behavioral burden well. It discloses that the secret 'whi_…' is returned only once, that the first issue grants a free credit with reason 'first_key', and that X-API-Key is an alias for Bearer auth. These are exactly the kind of non-obvious behaviors an agent needs.

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 with the core action. Most sentences add relevant context such as one-time secret exposure and free credit. A minor deduction: the 'Quote cost with quote_credits before mint_inbox' sentence is somewhat tangential to issuing a key and could distract from the tool's immediate purpose.

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 zero-parameter tool with no output schema, the description covers the essential operational details: endpoint, installation context, one-time secret, auth preference, and credit behavior. It does not describe possible errors or response format, but that is less critical given the tool's simplicity and the absence of parameters.

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 has zero parameterscars, so there is no parameter schema for the description to supplement. The baseline of 4 applies because no parameter documentation is needed, and the description still clarifies the endpoint and auth expectations.

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 a clear verb and resource: 'Mint a caller key (POST /keys).' This directly states the action and endpoint. It is also differentiated from siblings like revoke_key, rotate_key, and verify_key by framing this tool as the initial issuance action.

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 provides clear context for when this tool is used: at bot install, after discovering the sole advertised entry, and as the first key issuance. It also gives practical guidance like preferring Authorization: Bearer and quoting cost before mint_inbox)Skip. However, it does not explicitly state when not to use this tool versus alternatives.

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