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

Beyond the minimal annotations, the description discloses important non-obvious behaviors: the secret fdg_... is returned only once, the first issue grants a free credit with reason=first_key, Authorization: Bearer is preferred, and X-API-Key is an alias. This goes well beyond the annotated readOnly/destructive hints.

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?

Every sentence earns its place: purpose, entry-point flow, one-time secret, auth preference, credit grant, and cost-query reminder. The key action is front-loaded and the remaining details are densely packed without fluff.

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 is sufficiently complete: it identifies the endpoint, authentication method, one-time secret behavior, free-credit consequence, and the expected next step (quote_credits before digest_feed). An agent has what it needs to invoke the tool correctly.

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 schema has zero parameters and 100% description coverage, so the baseline is 4. The description adds relevant operational context (endpoint, auth, credit consequences) even though there are no parameters to document.

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 specific verb and resource, 'Mint a caller key (POST /keys)', which names exactly what the tool does and the HTTP endpoint. This clearly distinguishes it from sibling key lifecycle tools like verify_key, revoke_key, and rotate_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?

It gives clear contextual usage: the key is minted at bot install, starting from the llms.txt entry, and cost should be quoted with quote_credits before digest_feed. It does not explicitly state when not to use this tool versus its lifecycle siblings, so it falls short of a 5.

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