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

With no annotations, the description carries the transparency burden. It adds 'live' and 'current' to indicate real-time freshness, which is useful, but it does not disclose how the optional filters affect results, whether all plans are returned by default, or what the response structure looks like.

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, front-loaded sentence with no redundant information. It earns its place by stating exactly what the tool does.

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?

The tool has optional parameters and no output schema, yet the description fails to explain how the parameters work or what data will be returned. For an agent to invoke it correctly, more detail is needed on filtering behavior and response contents.

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 description provides zero explanation of the 'type' and 'countryCode' parameters, and the schema has no descriptions (0% coverage). An agent cannot infer what enum values 'country' or 'region' mean or how countryCode constrains results, making this a critical gap.

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 lists live Freeland prepaid travel eSIM plans and current Base USDC prices, using a specific verb ('List') and resource. It distinguishes itself from sibling get_* tools by being the only list_* operation.

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 implied by the name 'list_esim_plans' and the description, but there is no explicit when-to-use guidance or mention of alternatives. The lack of direction on optional parameters makes it less clear when to pass type or countryCode.

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