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

Annotations only state readOnlyHint=false and destructiveHint=false, so the description carries the burden of behavioral disclosure. It reveals that the secret is returned only once (a critical caveat), that the first issue grants free credit, the preferred Authorization header over the alias, and the entry point URL. These details go beyond the annotations and meaningfully inform the agent of side effects and constraints.

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 adds value: the action is front-loaded ('Mint a caller key'), followed by installation context, a one-time secret warning, auth preference, free-credit detail, and cost-check advice. The description is tightly packed with no filler, and the most critical instruction (secret returned once) is placed early.

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?

Given the tool has no parameters, no output schema, and minimal annotations, the description covers all essential aspects: the action, the endpoint, the one-time secret, the credit grant, and the recommended cost-check flow. It explains what to expect (secret) and how to behave (prefer Bearer, quote credits first). For a 0-param creation tool, this is highly complete.

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 parameters, so the schema provides full coverage (100%). Baseline for 0 params is 4. The description doesn't add parameter-specific info, but that's unnecessary since there are none. It does mention the endpoint and the returned secret, which loosely relates to expected output but not to parameters.

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 clearly states the tool's function: 'Mint a caller key (POST /keys)', which is a specific verb and resource. The title 'Issue caller key' reinforces this. It distinguishes itself from sibling tools like revoke_key, rotate_key, and verify_key by focusing on creation, making it unambiguous.

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 usage context: it mentions the bot install flow, that the secret is returned only once, and advises to quote cost with quote_credits before pdf_extract. It does not explicitly state when not to use it or name alternatives, but the context strongly implies it's the initial step for obtaining a key. The guidance about authentication method and free credit also aids correct usage.

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