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

No annotations are provided, so the description carries the full burden. It does disclose a genuine behavioral trait — the required 'esim' scope (an auth requirement) — and that results include a 'from' price, which is useful context. However, it says nothing about pagination, result volume, or response shape.

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?

A single tightly packed sentence plus the scope requirement, with the most important content (what is listed and the price signal) front-loaded. Zero waste.

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 no-parameter, no-annotation lister with no output schema, the description covers what it returns and the access requirement. The main omission is any hint about result size or pagination, which is minor for this simple tool.

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 tool takes zero parameters, so per the rubric the baseline is 4. There is no parameter meaning for the description to clarify, and it adds no misinformation.

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 names the resource (eSIM destinations) and enumerates its contents — countries, regions, and global plans with a 'from' price — which separates it from siblings like list_esim_packages and list_countries. It is a noun phrase rather than an explicit verb, but the listing intent is unambiguous.

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?

There is no explicit when-to-use guidance and no named alternative among the many esim siblings (list_esim_packages, quote_esim, order_esim). Usage is only implied by context — browsing destinations before ordering. The only usage-adjacent statement is the scope prerequisite.

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