Buy the owner-approved credit pack on their saved card, off-session — only when auto-recharge is ACTIVE and only within its monthly cap. Idempotent: the same idempotencyKey never charges twice. Returns 202 while Whop processes it; poll autoshort_get_credit_balance. Without auto-recharge use autoshort_get_buy_credits_url.
| Name | Required | Description | Default |
|---|---|---|---|
| idempotencyKey | Yes | A new unique key per purchase; reuse it only to retry the same purchase. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare idempotent/readOnly=false/destructive=false, and the description adds substantive context beyond them: off-session charging against a saved card, the 202 async response, the follow-up poll via autoshort_get_credit_balance, and the guarantee that a repeated idempotencyKey never double-charges.
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?
Four short sentences, front-loaded with the action and preconditions, then idempotency, then return/polling behavior, then the alternative. 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?
No output schema exists, and the description covers the async return code plus the polling tool needed to resolve the outcome, and the fallback path. An agent has everything required to invoke and follow up correctly.
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 parameter is already documented. The description still reinforces the idempotencyKey contract ('same idempotencyKey never charges twice'), linking the parameter to observable behavior rather than just restating the schema.
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 the owner-approved credit pack on their saved card, off-session') with the exact preconditions. It is clearly distinguishable from autoshort_get_buy_credits_url, which it names as the non-auto-recharge path.
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?
Explicit when-to-use gates: only when auto-recharge is ACTIVE and within its monthly cap. It also names the alternative for the negative case ('Without auto-recharge use autoshort_get_buy_credits_url'), so the routing decision is fully specified.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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