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

Annotations declare a non-readonly, open-world, non-idempotent write, and the description adds genuinely new behavior: it returns a Stripe Checkout link for a human to pay and credits only arrive once payment completes. That asynchronous, human-in-the-loop semantics is not derivable from the annotations and is important for an agent to know.

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?

Three short sentences, front-loaded with the action, then the outcome, then the payment mechanics. No filler; the endpoint note is compact and useful for tracing behavior.

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?

Even without an output schema, the description explains what the caller gets back (a Stripe Checkout link) and when the effect lands (after payment completes), which is the critical missing piece for a payment tool. It omits error/failure behavior but is otherwise complete for a one-parameter tool.

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 100% and the single 'pack' parameter is fully documented with enum values and pricing in the schema itself. The description adds no syntax or selection guidance beyond that, so the baseline 3 applies.

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 ('Buy a credit pack') and ties it to the in-game purpose ('for resurrection'), which links it to the resurrect_creature sibling. It does not explicitly distinguish itself from get_credit_balance, but the verb+resource pairing is 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 implies the use case (needing credits to resurrect) and explains the payment flow, but gives no explicit when-to-use/when-not or pointer to alternatives like get_credit_balance for checking balance first.

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