DNS-Shop Product Card

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuine value beyond that by disclosing a data-semantics rule (price fields are None when absent, never 0) and pointing to a guide resource for error codes. It stops short of describing failure behavior or rate limits inline.

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 short, front-loaded lines with zero filler: the action first, then the one non-obvious data rule, then a pointer for deeper detail. Every sentence earns its place.

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 fields need not be enumerated, and error codes are deliberately delegated to the referenced guide resource. For a single-parameter read-only fetch this is essentially complete; the only soft spot is that the critical error information lives outside the definition.

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%, and the product_url parameter already carries a format constraint plus an example, so the schema does the heavy lifting. The description adds no meaning about the parameter itself, which is the expected baseline of 3 when the schema is complete.

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 gives a specific verb and resource ("Fetch one DNS-Shop product card") and names the marketplace, which separates it from the many sibling *_card tools for other sites. It does not explicitly contrast with dns_search, but the singular-card scope is clear from the wording.

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 only implied: an agent can infer this is the tool for a single known product page, with dns_search presumably for discovery. There is no explicit when-to-use statement, no prerequisites, and no named alternative for agents that have a product ID rather than a URL.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.