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

With no annotations, the description carries the full burden. It usefully discloses the return payload ('message text and extracted verification code when available'), implying an empty result is possible, but says nothing about timing/polling behavior, whether it blocks, or what happens for an inactive/unknown order.

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?

Two tight sentences, zero filler, with the core purpose front-loaded and the return behavior second. Every sentence 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?

No output schema exists, so the description's mention of returned message text and verification code is valuable, but for a polling-style check tool with zero annotations the absence of timing, retry, or failure semantics leaves meaningful gaps.

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 coverage, so the schema already fully documents orderId. The description adds no format or sourcing detail beyond the schema's 'order ID from order_number', so baseline 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+resource+scope: 'Check whether an SMS has been received on an active order.' An agent can distinguish it from generic message retrieval, though it never names the closest sibling (get_number_messages) to sharpen the boundary.

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 'on an active order' implies the usage context (verifying SMS for an in-flight order), but there is no explicit when-to-use, when-not-to-use, or named alternative such as get_number_messages. Usage must be inferred.

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