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

Annotations cover the safety profile (readOnly=false, openWorld=true, destructive=false), and the description adds substantial context beyond them: what a renewal does (repeats the original package, triggered near 10% remaining), that it spends money requiring a saved payment method, the default per-call confirmation behavior, cross-user reach requiring user consent, and the Cotlet API key requirement.

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?

Front-loaded with the core action, then preconditions and behavioral notes. The two confirmation-related sentences are slightly redundant but carry distinct information (default per-call confirmation vs. consent when reaching other people), so the length is mostly earned.

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 two-parameter mutation with no output schema, the description covers what an agent needs: preconditions, monetary side effect, auth requirement, and confirmation norms. Nothing required to invoke it correctly appears to be missing.

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%, so both parameters are already documented (enabled true/false semantics, esim_id from list_esims). The description adds no parameter-level detail beyond what the schema provides, so the baseline of 3 applies.

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?

States a specific verb and resource (turn renewals on or off for an eSIM) and scopes it with 'when it offers them.' An agent can distinguish this from siblings like airalo_buy_esim or airalo_top_up_esim without opening any schema.

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?

Gives clear applicability conditions and prerequisites: only when the eSIM offers renewals, not once data is exhausted or validity has ended, and requires a saved payment method. It does not explicitly name or route to alternative tools, which keeps it below 5.

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