Fetch the configurable option space for a per-order (configurable) product before requesting a quote, forwarded to the owning seller. Returns option groups, choices, quantity rules and surcharges. Fixed-price products have no schema; buy those with buy_product.
| Name | Required | Description | Default |
|---|---|---|---|
| product_id | Yes | The configurable product id from discovery. | |
| seller_mcp_url | Yes | mcp_ref.seller_mcp_url from a discovery result. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so description carries full burden. Discloses return content (option groups, choices, quantity rules, surcharges) and mentions forwarding to seller. Could be more explicit about being read-only, but 'fetch' implies that.
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 sentences, front-loaded with purpose, no redundant information.
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, but description explains return structure. Addresses edge case (fixed-price products). Differentiates well among 26 siblings.
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%, so description adds little beyond schema. It provides context for seller_mcp_url being from discovery, but baseline 3 is appropriate.
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?
Description clearly states verb (Fetch), resource (configurable option space for a per-order product), and distinguishes from buy_product for fixed-price products.
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?
Explicitly states when to use (before requesting a quote for configurable products) and when not to (fixed-price products, use buy_product). Also mentions forwarding to seller.
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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