Dated price observations per retailer, where available. Coverage and refresh times vary by source. These rows are asking prices, not proof that a discount or stock state is current. Every price carries observed_at and expires_at; do not quote after expires_at.
| Name | Required | Description | Default |
|---|---|---|---|
| days | No | 1 to 365, default 30 | |
| product_id | Yes | canonical product uuid, from search_products |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden and does well: discloses coverage/refresh variability, that rows are asking prices not proof of discount or stock, and that quotes require expires_at vigilance. It adds meaningful caveats about data freshness and reliability beyond the schema.
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, each earning its place: what the data is, its variability, and the critical expiry caveat. Front-loaded purpose and no waste.
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?
Covers freshness caveats well, but for a history tool with no output schema, it omits return shape (e.g., per-retailer rows, fields like price/currency) and lacks explicit routing vs get_current_prices. Adequate but with clear gaps.
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% with both parameters documented, including product_id source and days range/default. The description adds no parameter-level meaning beyond the schema, so 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?
The description states it returns dated price observations per retailer, a specific resource with temporal scoping. It implicitly contrasts with get_current_prices by emphasizing 'dated' and 'history', but does not explicitly name the sibling it differs from.
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?
Usage is implied: use for historical prices, noting variability and expiry. No explicit when/when-not guidance or reference to alternatives like get_current_prices or compare_prices despite clear siblings.
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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