Side-by-side comparison of two coins — machine mirror of the /comparer page: full specs (weight, purity, diameter, thickness, first mint year, design, mintage, face value), investment data (liquidity, French VAT, estimated premium) and best live dealer price for each.
| Name | Required | Description | Default |
|---|---|---|---|
| coin_a | Yes | First coin slug. | |
| coin_b | Yes | Second coin slug. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses the output content (specs, investment data, best price) and notes it mirrors a web page, but does not mention any read-only nature, potential network dependence for 'live' prices, or how the comparison behaves if coins are invalid. This is adequate but not rich.
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 sentence that front-loads the primary action ('Side-by-side comparison of two coins') and uses a colon-enclosed list to detail what is included. It is efficient, though the long list of fields makes it slightly dense.
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?
Given only two parameters and no output schema, the description provides a solid high-level overview of the returned data (specs, investment data, best live dealer price). It does not explain output format or errors, but for a comparison tool with this simplicity, it is fairly complete.
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 input schema already provides clear descriptions for both parameters ('First coin slug' and 'Second coin slug') with 100% coverage. The description does not add any extra meaning beyond the schema, so a 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 clearly states 'Side-by-side comparison of two coins' with a specific verb and resource. It enumerates the categories (specs, investment data, best live dealer price) and references the /comparer page, effectively distinguishing this from sibling tools like compare_prices or get_coin_specs by the comprehensive side-by-side nature.
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: use this when you need a side-by-side comparison of two coins. However, it does not explicitly state when to prefer this over alternatives (e.g., 'for just specs, use get_coin_specs') or provide exclusion criteria.
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.
