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

Annotations declare non-read-only, non-idempotent, non-destructive, but the description adds behavior the annotations cannot: no required arguments, each call produces a different secret, the secret is returned only once, it is not billed, and it is not drawn from the Toolweather quota. That is exactly the extra context an agent needs before minting credentials.

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 most important facts (what it mints, which tools consume it, don't over-call it) are front-loaded, and each subsequent sentence carries non-redundant information such as quota/safety caveats. 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?

For a zero-required-arg credential-minting tool with no output schema, the description covers invocation, return semantics ('Returns that secret once'), billing, quota, and the sibling alternative. Nothing an agent needs to call it correctly is missing.

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 already 100% and there is a single optional parameter, so the baseline is 3. The description usefully clarifies that label is a stored note rather than an auth secret, but it adds little beyond the schema text, which says virtually the same thing.

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 ('Mint one new SpendGate API key (sg_live_…)') and names the exact consumers (score_spend, get_quota). It also explicitly disambiguates from the sibling get_api_key by noting that one returns Toolweather tw_ keys, so an agent can route without opening either schema.

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?

Gives explicit when-to-use, when-not-to-use, and the alternative: use once and pass the secret as api_key, do not call every turn, and do not use it when a Toolweather key is needed (get_api_key). No inference is required.

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