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

Annotations already cover the non-read-only, non-idempotent profile, and the description adds substantial context beyond them: the 1,000 calls/day and 3-watch quotas, the one-time return of api_key that cannot be re-fetched, per-call secret uniqueness, the no-key fallback (50 calls/day), and the required X-API-Key header.

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?

Dense but front-loaded: the core action and its constraints come first, followed by return values and edge cases. Every sentence carries distinct operational information with 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 output schema present, the description compensates fully by documenting the return payload (api_key, daily_limit, watches_limit) and the one-time-retrieval caveat. An agent has everything needed to call it correctly and only once.

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?

Zero parameters, so baseline is 4. The description reinforces this and adds meaning by noting 'Takes no arguments; the caller network is the limit,' explaining that per-network rate limiting substitutes for parameter-level control.

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 Toolweather API key') with the exact format prefix (tw_…) and scope. It explicitly distinguishes itself from the sibling key tools spendgate_get_api_key and paycheck_get_api_key by naming their return prefixes.

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 ('once per install', 'a few new keys per network per day, then reuse'), when-not ('do not call it every turn'), and alternatives ('do not use it when you need a SpendGate key … or a PayCheck key'). Nothing is left to inference.

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