Fetch one page of public Costco product review items with rating, author, and recommendation. Use costco_product for item details or costco_search to find a product.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Costco product id, e.g. from a search result's id field |
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | The tool result payload (shape varies per tool; see each tool's docs resource). |
Changes observed during successful MCP inspections.
Input schema / properties / id / descriptionAdded value: +"Costco product id, e.g. from a search result's id field"Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful behavior beyond that: results are paginated ('one page'), the reviews are 'public', and the shape of each item is disclosed. It doesn't state page-size or how to advance pages, which keeps it short of a 5.
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?
Two sentences, no filler. The payload description comes first and the routing guidance second, so it is properly front-loaded.
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?
An output schema exists, so return values need not be enumerated. Combined with the safety annotations, the description covers purpose, routing, and pagination context well enough for correct invocation.
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% for the single id parameter, so the schema already documents its meaning and origin. The description reinforces provenance ('costco_search to find a product') but adds no format or syntax detail beyond what the schema provides; 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 ('Fetch one page of') and resource ('public Costco product review items'), and enumerates the returned content (rating, author, recommendation). It is clearly distinguished from the sibling detail/search tools by naming them explicitly.
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 routes the agent: use costco_product for item details, costco_search to find a product, implying this tool is for the review list itself. Both the when-to-use and the alternatives are stated with their selecting conditions.
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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