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

With no annotations, the description carries the burden for behavioral disclosure. It does disclose the return fields (price, availability, product page URL), which is useful. However, it does not mention whether the operation is read-only (though implied by 'search'), any authentication needs, or rate limits. The disclosure is basic but not misleading.

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 two sentences with no wasteful words. It front-loads the action ('Search') and efficiently specifies both the scope and the result fields. 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?

Given four optional parameters and no output schema, the description adequately explains what is returned (matching products with price, availability, and URL). It is complete enough for a search operation, though it could mention that get_product is available for detail retrieval, but that is not strictly necessary.

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 description coverage is 100% and all parameters have detailed descriptions, including the enum mapping for type. The tool description adds no additional parameter behavior beyond the schema, so a baseline of 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 the tool searches a catalog of gift cards, top-ups, and eSIM plans, and returns matching products with price, availability, and URL. It uses a specific verb and resource but does not explicitly differentiate from sibling tool get_product, so it gets a 4 rather than 5.

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: it is for searching the catalog and returning matching products. However, it provides no explicit guidance on when to use this tool versus get_product, nor any exclusions or alternative scenarios. This is implied usage without a clear decision framework.

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