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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful payload context (the response includes the eSIM's ICCID, install links, and pending state), but says nothing about error behavior for an unknown reference or any auth constraints.

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 sentence that is front-loaded with the core action and resource, with no filler. It is arguably too terse for the tool's needs, but as a structural matter every clause earns its place.

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 simple one-parameter read tool with annotations covering the safety profile and no output schema, the description conveys the key return content (eSIM details), which is what the agent most needs. Only the missing-reference/error case and identifier format are left unaddressed.

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 0% for the single order_reference parameter, so the description carries the burden: 'by reference' signals that this is an identifier lookup key. That is helpful but thin — no format, example, or validity rules are given to compensate for the undocumented schema field.

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: retrieve one order, keyed by reference, with the notable side benefit of the attached eSIM data. This is clearly distinct from the plural list_orders sibling. It stops short of naming a sibling explicitly, so it sits just under the top mark.

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 phrase 'One order by reference' implies a single-record lookup as opposed to the sibling list_orders, so usage is implied rather than stated. There is no explicit when-to-use, when-not-to-use, or named alternative, leaving the agent to infer the routing.

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