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

With no annotations, the description carries the full transparency burden. It discloses key behavior by stating that the readiness check excludes unrelated card-provider and treasury gates. Yet it omits details about return type or potential errors, which are not covered elsewhere.

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 sentence that is front-loaded with the main action ('Return eSIM-only readiness') and includes no extraneous content. Every word contributes to understanding the tool's purpose and scope.

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 zero-parameter, read-only tool with no output schema, the description is nearly complete. It clearly indicates what is returned and what is excluded, but could more explicitly describe the return value shape (e.g., boolean vs. object), which would aid agent expectations.

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 has zero parameters, so there is no parameter-specific information to add. The baseline for zero-parameter tools is 4, and the description appropriately provides no irrelevant parameter details.

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 'Return eSIM-only readiness' with a specific verb and resource. The qualifier 'without unrelated card-provider or treasury gates' effectively distinguishes it from the sibling get_readiness tool.

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 its use case by focusing on eSIM-only readiness and explicitly excluding card-provider and treasury gates. However, it does not name the alternative get_readiness or provide explicit when-to-use/when-not-to-use guidance.

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