Full data sheet for a gold or silver investment coin: weight, purity, diameter, thickness, first mint year, design type and design changes over time, mintage, face value, liquidity score, French VAT rate, estimated premium vs spot, and unique highlights.
| Name | Required | Description | Default |
|---|---|---|---|
| coin | Yes | Coin slug or name. Ex: krugerrand, maple-leaf, napoleon. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the burden. It lists return fields but doesn't disclose behavior on missing/invalid slugs, error handling, or any side effects. This is sufficient for a straightforward read operation but lacks deeper behavioral context.
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 a single, front-loaded sentence that lists all returned attributes, which is both informative and structured. While the list is long, every item serves to set expectations for the tool's output.
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 a single parameter and no output schema, the description provides a thorough enumeration of fields, including niche details like French VAT rate and liquidity score. It lacks mention of error handling for unknown coins, but the field list makes the tool's behavior largely predictable.
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 schema already fully describes the sole parameter 'coin' with examples. The description adds context that it's for gold or silver investment coins, reinforcing the parameter's semantic domain, but it doesn't introduce additional syntax or format details.
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 clearly defines the tool as providing a full data sheet for a gold or silver investment coin, listing specific attributes like weight, purity, and mintage. This distinguishes it from siblings like compare_prices or list_dealers, which serve different purposes.
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 implies usage for retrieving comprehensive specs for a single coin. It doesn't explicitly name alternatives or exclusions, but the context is clear and the sibling names (e.g., compare_prices, search_coins) make when to use this tool unambiguous.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
compare_prices and get_best_price are nearly identical: both accept a coin slug or name and return the same ranked list of all 11 dealer prices with in-stock status. The other tools are distinct, but this clear functional overlap creates real selection ambiguity.
All six tools follow a consistent lowercase snake_case verb_noun pattern: compare_coins, compare_prices, get_best_price, get_coin_specs, list_dealers, search_coins. Verbs are action-oriented and predictable, making the tool surface easy to navigate.
Six tools is a reasonable size for a bullion coin information and price comparison server. The count is not excessive, though one tool is largely redundant with another, so the set is slightly less tight than it could be.
The server covers the apparent domain well: searching the catalog, retrieving full coin specs, comparing dealer prices, doing side-by-side coin comparisons, and listing dealers. Minor gaps like a dedicated spot price tool or dealer detail view exist, but core informational needs are covered.
