Resolve public product or listing availability with explicit normalized states. It reports only provider evidence and never infers inventory, reserves items or places an order. Price: $0.002 USDC per successful call.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | Public HTTP(S) URL to inspect, resolve, or compare. | |
| variant | No | Public identifiers value used to scope this lookup. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden and does well: it states the tool only reports provider evidence, never infers inventory, never reserves, and never places an order, and it discloses a per-call cost of $0.002 USDC. It still omits auth requirements, rate limits, and error/failure behavior, which keeps it out of the top score.
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 tight sentences with the core function front-loaded, followed by the negative guarantees and then the price. Every sentence carries information and none is redundant.
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 no output schema, the description should say more about what is returned; 'explicit normalized states' hints at a return shape but never enumerates the states, so an agent cannot fully predict the response. It is otherwise adequate for a two-parameter read-only resolver.
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 schema already documents both the url and the nested variant parameter. The description adds no syntax, format, or scoping detail beyond what the schema says, which is the expected baseline when structured fields do the heavy lifting.
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 pairs a specific verb ('resolve') with a specific resource ('public product or listing availability') and adds scope ('explicit normalized states'). It does not, however, differentiate itself from the nearest sibling, commerce_buyability, leaving the agent to infer the boundary between availability and buyability.
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?
There is no explicit statement of when to choose this tool over commerce_buyability or the other preflight/resolve siblings. The 'never infers inventory, reserves items or places an order' line is a behavioral guarantee about side effects, not usage guidance, so the agent gets little help routing between the six tools.
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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