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

Annotations already indicate this is not read-only and not idempotent, and the description adds that it involves Stripe Checkout and human operator action. It does not disclose the full flow (e.g., whether credits are applied immediately or only after payment), but the annotation coverage lowers the burden. The description adds some context beyond annotations without contradiction.

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 a single, front-loaded sentence that begins with the action verb 'Generate' and immediately communicates purpose. Every word is informative, and there is no redundancy or 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 tool with only two parameters and no output schema, the description adequately conveys the core purpose and context. It explains the external integration (Stripe) and the actor (human operator). It stops short of describing follow-up steps or edge cases, but given the simplicity of the tool, the description is sufficiently 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?

Schema description coverage is 100%, so the baseline is 3. The description does not add extra parameter semantics beyond what the schema already provides for api_key and tier. It mentions prepaid credits and existing API key but does not elaborate on tier options or validation, making this a neutral contribution.

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 generates a Stripe Checkout link for adding prepaid credits to an existing ActionGate API key. It uses a specific verb (generate) and resource (Stripe Checkout link), and distinguishes itself from siblings like request_api_key (which creates new keys) and balance (which checks balance).

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: it is for a human operator to add credits to an existing key. It implies use when an existing key needs topping up, but does not explicitly mention alternatives or exclusion criteria. The 'existing' qualifier and mention of 'human operator' offer practical guidance without naming sibling tools.

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