Buy a product. Returns a Stripe checkout_url — open it (or give it to your human) to pay. Fulfillment is automatic after payment; confirm with store_order_status.
| Name | Required | Description | Default |
|---|---|---|---|
| api_key | Yes | Your DACIX API key (dacix_sk_...). Get one with store_register. | |
| quantity | No | ||
| product_id | Yes | From store_catalog, e.g. credits-starter |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Without annotations, the description discloses the key behavior: returns a Stripe checkout URL for payment, automatic fulfillment after payment, and suggests confirming with store_order_status. It does not mention potential side effects or authorization beyond the api_key, but it covers the main workflow adequately.
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 extremely concise at two sentences, with no wasted words. The most important information ('Buy a product') is front-loaded, and every sentence adds value.
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?
Given the tool's moderate complexity (3 parameters, no output schema, no annotations), the description covers the essential behavior and next steps. It lacks error handling details or elaboration on the checkout process, but it is sufficient for an AI agent to use the tool 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?
The description does not add any parameter-level details beyond what is already in the input schema. The schema covers 67% of parameters with descriptions, and the description restates nothing about parameters. The baseline of 3 is appropriate given the schema coverage.
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 starts with 'Buy a product' which clearly states the action and resource. It then explains the specific behavior (returns Stripe checkout URL) and distinguishes from sibling tools like store_catalog and store_order_status by mentioning the checkout process and automatic fulfillment.
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 guidance on how to use the tool's output: open the checkout URL or give it to the user to pay. It also advises confirming fulfillment with store_order_status. While it doesn't explicitly state when not to use the tool, the context is sufficient for an agent to decide.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.