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

Annotations already establish readOnly, idempotent, non-destructive, closed-world semantics, so the bar is lower. The description still adds meaningful behavioral context the annotations cannot convey: eventual consistency (provisioning usually finishes within a minute) and the instruction that an empty eSIM list right after payment is normal and should be re-checked shortly.

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?

Four tight sentences, each doing work: purpose, identification, timing caveat, next step. The core purpose is front-loaded and the routing hint comes last where it belongs.

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?

An output schema exists, so return values need not be explained. Between the description's lifecycle framing, retry guidance, and next-step routing, an agent has everything needed to call this correctly and interpret an empty result.

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 baseline is 3. The description reinforces that both order id and email are needed and explains the email's role (the order id alone does not identify a buyer), but adds little beyond what the schema fields already state.

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 (check an eSIM order) and names exactly what it reports: completion status and whether eSIMs have been provisioned. It is clearly distinguishable from siblings like get-esim-activation, which the description positions as the downstream step.

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 explicit when-to-use context (after payment), the identifiers required and where to find them (buyer's confirmation email), guidance for the ambiguous 'paid but no eSIMs yet' case, and an explicit hand-off to get-esim-activation once an eSIM is listed.

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