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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds little beyond the purpose—no mention of result ordering, pagination, or filtering behavior. It simply restates the search scope, which provides some context but not rich behavioral detail.

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, concise sentence that immediately conveys the tool's purpose. No wasted words, perfect front-loading.

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?

With an output schema present and full schema documentation for parameters, the description is largely complete for a search tool. However, it could have added a note about what constitutes a 'destination' (e.g., country name or code) or how results are ordered, but the schema already covers the country format. Overall, sufficient but not exhaustive.

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 description coverage is 100%; all three parameters (country, min_data_mb, max_duration_days) have descriptive text. The tool description does not add extra parameter semantics beyond what the schema already provides, so the 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 the action (Find), the resource (travel eSIM data plans), and the scope (available for a destination). This distinguishes it from sibling tools like get_plan_details, which focuses on a single plan's details.

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: when you need to find plans for a destination. However, it does not explicitly mention when not to use it or provide alternatives, such as using get_plan_details for a specific plan's details. The context is clear but the guidance is not fully explicit.

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