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

No annotations are provided, so the description carries the full burden and does so well: it enumerates all seven status values with their meaning, specifies a ~30s retry cadence for 'processing', and supplies a fallback action (contact support@altesim.com) for 'manual_review'. It does not cover auth requirements or rate limits, keeping it below a 5.

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 and the source parameter, with the long status enumeration placed after. The enumeration is verbose but each status maps to a distinct agent behavior, so it earns its place; a slightly tighter grouping could still improve it.

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?

There is no output schema, so the description must describe returns — and it does, spelling out statuses and noting that 'ready' returns QR image(s) + ICCID(s). Combined with the explicit instruction never to assume payment succeeded, an agent has everything needed to call and interpret this tool.

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?

Only one parameter with 100% schema description coverage, so the schema already documents checkout_session_id fully. The description adds only that it comes from create_checkout, which is minor supplementary context — baseline 3 is correct.

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+resource ('Fetch the eSIM QR code(s) for an order') plus the intent ('to show the buyer directly'), and names the source tool (create_checkout). An agent can distinguish this immediately from the plan/destination/checkout siblings, none of which return QR codes.

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 context: pass the checkout_session_id from create_checkout, and use the returned status to tell the buyer what's happening. There are no real alternatives among siblings to exclude, but there is also no explicit when-not guidance, so it falls short of a 5.

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